0001564590-22-018911 | 10-Q | XBRL Viewer

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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Mar. 31, 2022	Apr. 28, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	MESA
Title of 12(b) Security	Common Stock, no par value
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	NV
Entity File Number	001-38626
Entity Tax Identification Number	85-0302351
Entity Address, Address Line One	410 North 44th Street
Entity Address, Address Line Two	Suite 700
Entity Address, City or Town	Phoenix
Entity Address, Postal Zip Code	85008
City Area Code	602
Local Phone Number	685-4000
Entity Address, State or Province	AZ
Entity Registrant Name	MESA AIR GROUP, INC.
Entity Central Index Key	0000810332
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		36,131,745

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Current assets:
Cash and cash equivalents	$ 75,896	$ 120,517
Restricted cash	3,351	3,350
Receivables, net	6,849	3,167
Expendable parts and supplies, net	26,255	24,467
Prepaid expenses and other current assets	7,608	6,885
Total current assets	119,959	158,386
Property and equipment, net	1,064,349	1,151,891
Intangible assets, net	6,281	6,792
Lease and equipment deposits	8,371	6,808
Operating lease right-of-use assets	79,706	93,100
Deferred heavy maintenance, net	5,289	3,499
Assets held for sale	36,528
Other assets	32,873	36,121
Total assets	1,353,356	1,456,597
Current liabilities:
Current portion of long-term debt and finance leases	111,671	111,710
Current portion of deferred revenue	2,675	6,298
Current maturities of operating leases	16,601	32,652
Accounts payable	76,733	61,476
Accrued compensation	10,285	12,399
Other accrued expenses	31,406	33,657
Total current liabilities	249,371	258,192
Noncurrent liabilities:
Long-term debt and finance leases, excluding current portion	521,457	539,700
Noncurrent operating lease liabilities	29,936	33,991
Deferred credits	3,508	3,934
Deferred income taxes	53,281	69,940
Deferred revenue, net of current portion	26,868	28,202
Other noncurrent liabilities	36,394	34,591
Total noncurrent liabilities	671,444	710,358
Total liabilities	920,815	968,550
Commitments and contingencies (Note 16)
Stockholders' equity:
Preferred stock of no par value, 5,000,000 shares authorized; no shares issued and outstanding
Common stock of no par value and additional paid-in capital, 125,000,000 shares authorized; 36,126,724 (2022) and 35,958,759 (2021) shares issued and outstanding, 4,899,497 (2022) and 4,899,497 (2021) warrants issued and outstanding	257,923	256,372
Retained earnings	174,618	231,675
Total stockholders' equity	432,541	488,047
Total liabilities and stockholders' equity	$ 1,353,356	$ 1,456,597

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Sep. 30, 2021
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, no par value	$ 0	$ 0
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	36,126,724	35,958,759
Common stock, shares outstanding	36,126,724	35,958,759
Common stock, warrants issued	4,899,497	4,899,497
Common stock, warrants outstanding	4,899,497	4,899,497

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Operating revenues:
Total operating revenues	$ 123,213	$ 97,280	$ 270,970	$ 247,651
Operating expenses:
Flight operations	42,410	37,403	90,008	74,367
Maintenance	47,357	51,773	106,338	104,637
Aircraft rent	9,434	9,992	19,020	20,040
General and administrative	7,860	11,164	20,438	24,237
Depreciation and amortization	20,747	20,705	41,775	41,175
Lease termination		4,508		4,508
Impairment of assets held for sale	39,475		39,475
Other operating expenses	685	941	2,657	2,232
Government grant recognition		(55,967)		(67,278)
Total operating expenses	167,968	80,519	319,711	203,918
Operating income (loss)	(44,755)	16,761	(48,741)	43,733
Other income (expense), net:
Interest expense	(8,120)	(8,755)	(16,050)	(17,837)
Interest income	42	79	93	205
Loss on investments, net	(2,261)		(8,723)
Other income (expense), net	(71)	(506)	(130)	417
Total other expense, net	(10,410)	(9,182)	(24,810)	(17,215)
Income (loss) before taxes	(55,165)	7,579	(73,551)	26,518
Income tax expense (benefit)	(12,382)	1,890	(16,494)	6,711
Net income (loss) and comprehensive income (loss)	$ (42,783)	$ 5,689	$ (57,057)	$ 19,807
Net income (loss) per share attributable to common shareholders
Basic	$ (1.19)	$ 0.16	$ (1.58)	$ 0.56
Diluted	$ (1.19)	$ 0.14	$ (1.58)	$ 0.52
Weighted-average common shares outstanding
Basic	36,048	35,628	36,005	35,579
Diluted	36,048	39,432	36,005	38,382
Contract Revenue [Member]
Operating revenues:
Total operating revenues	$ 111,988	$ 81,712	$ 248,882	$ 208,870
Pass Through and Other Revenue [Member]
Operating revenues:
Total operating revenues	$ 11,225	$ 15,568	$ 22,088	$ 38,781

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Number of Warrants [Member]	Common Stock and Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning balance at Sep. 30, 2020	$ 457,859			$ 242,772	$ 215,087
Beginning balance, shares at Sep. 30, 2020		35,526,918
Stock compensation expense	850			850
Repurchased shares	(19)			(19)
Repurchased shares, shares		(2,256)
Restricted shares issued, shares		7,500
Issuance of warrants, net of issuance costs	11,489			11,489
Issuance of warrants, net of issuance costs, shares			4,899,497
Net income (loss)	14,118				14,118
Ending balance at Dec. 31, 2020	484,297			255,092	229,205
Ending balance, shares at Dec. 31, 2020		35,532,162	4,899,497
Beginning balance at Sep. 30, 2020	457,859			242,772	215,087
Beginning balance, shares at Sep. 30, 2020		35,526,918
Net income (loss)	19,807
Ending balance at Mar. 31, 2021	490,844			255,950	234,894
Ending balance, shares at Mar. 31, 2021		35,700,161	4,899,497
Beginning balance at Dec. 31, 2020	484,297			255,092	229,205
Beginning balance, shares at Dec. 31, 2020		35,532,162	4,899,497
Stock compensation expense	808			808
Repurchased shares	(157)			(157)
Repurchased shares, shares		(14,680)
Restricted shares issued, shares		124,609
Employee share purchases	207			207
Employee share purchases, shares		58,070
Net income (loss)	5,689				5,689
Ending balance at Mar. 31, 2021	490,844			255,950	234,894
Ending balance, shares at Mar. 31, 2021		35,700,161	4,899,497
Beginning balance at Sep. 30, 2021	488,047			256,372	231,675
Beginning balance, shares at Sep. 30, 2021		35,958,759	4,899,497
Stock compensation expense	716			716
Repurchased shares	(15)			(15)
Repurchased shares, shares		(2,275)
Restricted shares issued, shares		7,500
Net income (loss)	(14,274)				(14,274)
Ending balance at Dec. 31, 2021	474,474			257,073	217,401
Ending balance, shares at Dec. 31, 2021		35,963,984	4,899,497
Beginning balance at Sep. 30, 2021	488,047			256,372	231,675
Beginning balance, shares at Sep. 30, 2021		35,958,759	4,899,497
Repurchased shares		$ (100)
Net income (loss)	(57,057)
Ending balance at Mar. 31, 2022	432,541			257,923	174,618
Ending balance, shares at Mar. 31, 2022		36,126,724	4,899,497
Beginning balance at Dec. 31, 2021	474,474			257,073	217,401
Beginning balance, shares at Dec. 31, 2021		35,963,984	4,899,497
Stock compensation expense	671			671
Repurchased shares	(60)			(60)
Repurchased shares, shares		(13,421)
Restricted shares issued, shares		122,594
Employee share purchases	239			239
Employee share purchases, shares		53,567
Net income (loss)	(42,783)				(42,783)
Ending balance at Mar. 31, 2022	$ 432,541			$ 257,923	$ 174,618
Ending balance, shares at Mar. 31, 2022		36,126,724	4,899,497

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income (loss)	$ (57,057)	$ 19,807
Adjustments to reconcile net income (loss) to net cash flows provided by operating activities:
Depreciation and amortization	41,775	41,175
Stock compensation expense	1,387	1,658
Loss on investments, net	8,723
Deferred income taxes	(16,659)	6,654
Amortization of deferred credits	(426)	(2,258)
Amortization of debt discount and issuance costs and accretion of interest into long-term debt	6,605	4,994
Lease termination		4,508
Impairment of assets held for sale	39,475
Other	910	(903)
Changes in assets and liabilities:
Receivables	(3,682)	(155)
Expendable parts and supplies	(2,249)	(84)
Prepaid expenses and other operating assets and liabilities	(1,741)	(1,988)
Accounts payable	14,413	15,470
Deferred heavy maintenance, net	(2,430)
Deferred revenue	(4,957)	10,099
Accrued expenses and other liabilities	(7,048)	(14,092)
Operating lease right-of-use assets and liabilities	(7,081)	(6,311)
Net cash provided by operating activities	9,958	78,574
Cash flows from investing activities:
Capital expenditures	(22,850)	(5,261)
Investments in equity securities	(200)
Payments of equipment and other deposits	(6,954)	(6,954)
Returns of equipment and other deposits		540
Net cash used in investing activities	(30,004)	(11,675)
Cash flows from financing activities:
Proceeds from long-term debt	30,811	195,000
Proceeds from issuance of common stock under ESPP	239
Principal payments on long-term debt and finance leases	(53,135)	(212,020)
Payments of debt and warrant issuance costs	(2,414)	(1,326)
Repurchase of stock	(75)	(176)
Net cash used in financing activities	(24,574)	(18,522)
Net change in cash, cash equivalents and restricted cash	(44,620)	48,377
Cash, cash equivalents and restricted cash at beginning of period	123,867	102,841
Cash, cash equivalents and restricted cash at end of period	79,247	151,218
Supplemental cash flow information
Cash paid for interest	9,464	16,922
Cash paid for income taxes, net	176	49
Operating lease payments in operating cash flows	26,224	25,716
Supplemental non-cash operating activities
Right-of-use assets obtained (disposed) in exchange for lease liabilities	4,870	(320)
Supplemental non-cash financing activities
Investments in warrants to purchase common stock	3,260	16,374
Debt issuance cost related to loan agreement with US Department of the Treasury		$ (1,887)
Accrued capital expenditures	$ 1,283

Organization and Operations

6 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Operations

1.	Organization and Operations

About Mesa Air Group, Inc.

Headquartered in Phoenix, Arizona, Mesa Air Group, Inc. ("Mesa" or the "Company") is the holding company of Mesa Airlines, Inc. ("Mesa Airlines"), a regional air carrier providing scheduled flight service to 110 cities in 40 states, the District of Columbia, the Bahamas, and Mexico as well as cargo flight services out of Cincinnati/Northern Kentucky International Airport. As of March 31, 2022, Mesa’s fleet consisted of 168 aircraft which were operated under the Company’s Capacity Purchase Agreements (“CPAs”) and Flight Services Agreement (“FSA”), leased to a third party, held for sale or maintained as operational spares, with approximately 349 daily departures and 2,800 employees. Mesa operates all of its flights as either American Eagle, United Express, or DHL Express flights pursuant to the terms of CPAs entered into with American Airlines, Inc. (“American”) and United Airlines, Inc. (“United”) and FSA with DHL Network Operations (USA), Inc. (“DHL”) (each, our “major partner”).

The CPAs between us and our major partners involve a revenue-guarantee arrangement whereby the major partner pays fixed-fees for each aircraft under contract, departure, flight hour (measured from takeoff to landing, excluding taxi time) or block hour (measured from takeoff to landing, including taxi time), and reimbursement of certain direct operating expenses in exchange for providing flight services. The major partners also pay certain expenses directly to suppliers, such as fuel, ground operations and landing fees. Under the terms of these CPAs, the major partner controls route selection, pricing, and seat inventories, reducing our exposure to fluctuations in passenger traffic, fare levels, and fuel prices. Under our FSA with DHL, we receive a fee per block hour with a minimum block hour guarantee in exchange for providing cargo flight services. Ground support expenses including fueling and airport fees are paid directly by DHL.

American Capacity Purchase Agreement

As of March 31, 2022, we operated 40 CRJ-900 aircraft under an Amended and Restated Capacity Purchase Agreement with American dated November 19, 2020 (as amended, the “American CPA”). In exchange for providing passenger flight services, we receive a fixed monthly minimum amount per aircraft under contract plus certain additional amounts based upon the number of flights and block hours flown during each month. In addition, we may also receive incentives or incur penalties based upon our operational performance, including controllable on-time departure (“CD0”) and controllable flight completion (“CCF”) percentages. American also reimburses us for certain costs on an actual basis, including passenger liability and hull insurance and aircraft property taxes. Other expenses, including fuel and certain landing fees, are directly paid to suppliers by American. In addition, American also provides, at no cost to us, certain ground handling and customer service functions as well as airport-related facilities and gates at American hubs and cities where we operate. The American CPA expires on December 31, 2025.

Our American CPA is subject to termination prior to its expiration in various circumstances including:

•

If either American or we become insolvent, file for bankruptcy, or fail to pay the debts as they become due, the non-defaulting party may terminate the agreement;

•

If either we or American fail to perform the covenants, conditions, or provisions of the American CPA, subject to certain notice and cure rights, the non-defaulting party may terminate the agreement;

•

If, at any time during the term of the American CPA, the number of covered aircraft is less than twenty (20);

•

If we are required by the United States Federal Aviation Administration (“FAA”) or the United States Department of Transportation (“DOT”) to suspend operations and we have not resumed operations within three business days, except as a result of an emergency airworthiness directive from the FAA affecting all similarly equipped aircraft;

•

If either our CCF or CD0 falls below certain levels for a specified period of time;

•

Upon the occurrence of a force majeure event (as defined in the American CPA) that lasts for a specified period of consecutive days and affects our ability to operate scheduled flights, including a future epidemic or pandemic;

•

If a labor dispute affects our ability to operate over a specified number of days or we operate in violation of any existing American collective bargaining agreement; or

•

Upon a change in our ownership or control without the written approval of American.

Under the American CPA, American has the option in its sole discretion to withdraw up to: (i) 10 aircraft during calendar year 2021, (ii) five aircraft during each of calendar years 2022 and 2023, and (iii) during the period from January 1, 2024 to July 31, 2024, American can remove the first 20 aircraft to the extent not otherwise removed in 2021 – 2023, and thereafter American has the right to remove the remaining 20 aircraft. American also has the right and option to withdraw a specified number of aircraft upon each occurrence of the following:

•

If our CCF falls below certain levels for a specified period of time, American may withdraw one aircraft;

•

If our CD0 falls below certain levels for a specified period of time, American may withdraw one aircraft;

•

If we fail to satisfactorily complete established cabin interior program requirements by certain deadlines, American may withdraw one aircraft; or

•

If our block hour utilization falls below certain levels for a specified period of time, American may withdraw a specified number of aircraft.

For the months of November and December 2021 and January 2022, we did not meet the CCF or CD0 minimum performance levels under the American CPA. Under the terms of the American CPA, the failure to meet the CCF or CD0 minimum performance levels for three (3) consecutive months gives American the right to terminate the CPA upon 90 days' notice and to provide a wind-down schedule for the aircraft covered under the American CPA. American agreed to waive any default arising out of the failure to meet the CCF or CD0 performance levels in January, which eliminated the right to terminate the American CPA for failure to meet the CD0 and CCF performance levels for the three (3) consecutive months ended January 2022, and agreed to reset the 3-consecutive month period to commence with the month of February 2022. Additionally, American has the right to remove two (2) additional aircraft from the CPA, one (1) aircraft for not meeting the CD0 minimum performance level for two consecutive months and one (1) aircraft for not meeting the CCF minimum performance level for two (2) consecutive months. American also agreed to waive its right to remove two (2) aircraft in connection with missing the November and December 2021 CCF and CD0 minimum performance levels. In the future, American has the right to remove additional aircraft should we fail to meet the CCF or CD0 minimum performance levels in subsequent two (2) consecutive month periods.

In March 2022, we amended our American CPA to, among other things, modify certain penalty and incentive compensation as defined in the American CPA.

United Capacity Purchase Agreement

As of March 31, 2022, we operated 60 E-175 and 20 E-175LL aircraft under a Second Amended and Restated Capacity Purchase Agreement with United dated November 4, 2020 (as amended, the “United CPA”). In exchange for providing passenger flight services, we receive a fixed monthly minimum amount per aircraft under contract plus certain additional amounts based upon the number of flights and block hours flown and the results of passenger satisfaction surveys. United reimburses us for certain costs on an actual basis, including property tax per aircraft and passenger liability insurance. United also reimburses us on a pass-through basis for all costs related to heavy airframe and engine maintenance, landing gear, auxiliary power units ("APUs"), and component maintenance for the E-175 aircraft owned by United. Other expenses, including fuel and certain landing fees, are directly paid to suppliers by United.

Under our United CPA, United owns 42 of the 60 E-175 aircraft and all of the E-175LL aircraft and leases them to us at nominal amounts. The E-175 aircraft owned by United and leased to us have terms expiring between 2024 and 2028, and the 18 E-175 aircraft owned by us have terms expiring in 2028. The E-175LL aircraft have terms expiring between 2032 and 2033.

Pursuant to the United CPA, we agreed to lease our CRJ-700 aircraft to another United Express service provider for a term of nine (9) years. We ceased operating our CRJ-700 fleet in February 2021 in connection with the transfer of those aircraft into a lease agreement, and as of March 31, 2022, have entered into agreements to lease 18 of our 20 CRJ-700 aircraft.

Our United CPA is subject to termination rights prior to its expiration in various circumstances including:

•

If certain operational performance factors fall below a specified percentage for a specified time, subject to notice under certain circumstances;

•

If we fail to perform the material covenants, agreements, terms or conditions of our United CPA or similar agreements with United, subject to thirty (30) days' notice and cure rights;

•

If either United or we become insolvent, file bankruptcy, or fail to pay debts when due, the non-defaulting party may terminate the agreement;

•

If we merge with, or if control of us is acquired by another air carrier or a corporation directly or indirectly owning or controlling another air carrier;

•

United, subject to certain conditions, including the payment of certain costs tied to aircraft type, may terminate the agreement in its discretion, or remove E-175 aircraft from service, by giving us notice of 90 days or more;

•

If United elects to terminate our United CPA in its entirety or permanently remove select aircraft from service, we are permitted to return any of the affected E-175 aircraft leased from United at no cost to us; and

•

Commencing five (5) years after the actual in-service date, United has the right to remove the E-175 aircraft from service by giving us notice of 90 days or more, subject to certain conditions, including the payment of certain wind-down expenses plus, if removed prior to the ten (10) year anniversary of the in-service date, certain accelerated margin payments.

DHL Flight Services Agreement

On December 20, 2019, we entered into a Flight Services Agreement with DHL (the “DHL FSA”). Under the terms of the DHL FSA, we operate two (2) Boeing 737-400F aircraft to provide cargo air transportation services. In exchange for providing cargo flight services, we receive a fee per block hour with a minimum block hour guarantee. We are eligible for a monthly performance bonus or subject to a monthly penalty based on timeliness and completion performance. Ground support including fueling and airport fees are paid directly by DHL.

Under our DHL FSA, DHL leases two (2) Boeing 737-400F aircraft and subleases them to us at nominal amounts. DHL reimburses us on a pass-through basis for all costs related to heavy maintenance including C-checks, off-wing engine maintenance and overhauls including life limited parts (“LLPs”), landing gear overhauls and LLPs, thrust reverser overhauls, and APU overhauls and LLPs. Certain items such as fuel, de-icing fluids, landing fees, aircraft ground handling fees, en-route navigation fees, and custom fees are paid directly to suppliers by DHL or otherwise reimbursed if incurred by us.

Our DHL FSA expires five (5) years from the commencement date of the first aircraft placed into service, which was in October 2020. DHL has the option to extend the agreement with respect to one or more aircraft for a period of one year with 90 days’ advance written notice.

Our DHL FSA is subject to termination rights prior to its expiration in various circumstances including:

•

If either party fails to comply with the obligations, warranties, representations, or undertakings under the DHL FSA, subject to certain notice and cure rights;

•

If either party is declared bankrupt or insolvent;

•

If we are unable to legally operate the aircraft under the DHL FSA for a specified number of days;

•

At any time after the first anniversary of the commencement date of the first aircraft placed in service with 90 days’ written notice;

•

If we fail to comply with performance standards for three consecutive measurement periods;

•

If we are subject to a labor incident that materially and adversely affects our ability to perform services under the DHL FSA for a specified number of days;

•

Upon a change in our control or ownership; and

•

DHL may terminate the agreement for a specific aircraft if it is subject to a total loss and we do not provide alternate services at our expense, or if the aircraft becomes unavailable for more than 30 days due to unscheduled maintenance.

Summary of Significant Accounting Policies

6 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Basis of Presentation

The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and include the accounts of the Company and its wholly owned operating subsidiaries. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification ("ASC") and Accounting Standards Update ("ASU") of the Financial Accounting Standards Board ("FASB"). All intercompany accounts and transactions have been eliminated in consolidation. Reclassifications of certain immaterial prior period amounts have been made to conform to the current period presentation.

These condensed consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements and notes thereto as of and for the year ended September 30, 2021 included in the Company's Annual Report on Form 10-K for the year ended September 30, 2021 on file with the U.S. Securities and Exchange Commission (the "SEC"). Information and footnote disclosures normally included in financial statements have been condensed or omitted in these condensed consolidated financial statements pursuant to the rules and regulations of the SEC and GAAP. These condensed consolidated financial statements reflect all adjustments that, in the opinion of management, are necessary to present fairly the results of operations for the interim periods presented.

The Company is an "emerging growth company," as defined in the Jumpstart Our Business Startups Act of 2012 (the "JOBS Act"), and may remain an emerging growth company until the last day of its fiscal year following the fifth anniversary of the Company’s initial public offering (“IPO”), subject to specified conditions. The JOBS Act provides that an emerging growth company can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. The Company has elected to "opt out" of such extended transition period, which means that when a standard is issued or revised and it has different application dates for public or private companies, the Company will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

Segment Reporting

As of March 31, 2022, our chief operating decision maker was the Chief Executive Officer. While we operate under two separate capacity purchase agreements and a flight services agreement, we do not manage our business based on any performance measure at the individual contract level. Our chief operating decision maker uses consolidated financial information to evaluate our performance and allocate resources, which is the same basis on which he communicates our results and performance to our Board of Directors. Accordingly, we have a single operating and reportable segment.

Use of Estimates

The preparation of the Company's condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, and expenses and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements. Actual results could differ from those estimates.

Contract Revenue and Pass-through and Other Revenue

We recognize contract revenue when the service is provided under our CPAs and FSA. Under the CPAs and FSA, our major partners generally pay for each departure, flight hour or block hour incurred, and an amount per aircraft in service each month with additional incentives or penalties based on flight completion, on-time performance, and other operating metrics. Our performance obligation is met as each flight is completed, and revenue is recognized and reflected in contract revenue.

We recognize pass-through revenue when the service is provided under our CPAs and FSA. Pass-through revenue represents reimbursements for certain direct expenses incurred including passenger liability and hull insurance, property taxes, other direct costs defined within the agreements, and major maintenance on aircraft leased from our major partners at nominal rates. Our performance obligation is met when each flight is completed or as the maintenance services are performed, and revenue is recognized and reflected in pass-through and other revenue.

We record deferred revenue when cash payments are received or are due from our major partners in advance of our performance. During the three and six months ended March 31, 2022, we recognized $0.8 million and $5.0 million of previously deferred revenue, respectively. Deferred revenue is recognized as flights are completed over the remaining terms of the respective contracts.

The deferred revenue balance as of March 31, 2022 represents our aggregate remaining performance obligations that will be recognized as revenue over the period in which the performance obligations are satisfied, and is expected to be recognized as revenue as follows (in thousands):

Periods Ending September 30,	Total Revenue
2022 (remainder of)	$	714
2023		5,051
2024		9,330
2025		6,253
2026		3,673
Thereafter		4,522
Total	$	29,543

A portion of our compensation under our CPAs with American and United is designed to reimburse the Company for certain aircraft ownership costs. Such costs include aircraft principal and interest debt service costs, aircraft depreciation, and interest expense or aircraft lease expense costs while the aircraft is under contract. We have concluded this component of the compensation under these agreements is lease revenue, as such agreements identify the "right of use" of a specific type and number of aircraft over a stated period of time. We account for the non-lease component under ASC 606 and account for the lease component under ASC 842. We allocate the consideration in the contract between the lease and non-lease components based on their stated contract prices, which is based on a cost basis approach representing our estimate of the stand-alone selling prices.

The lease revenue associated with our CPAs is accounted for as an operating lease and is reflected as contract revenue in the condensed consolidated statements of operations. We recognized $39.5 million and $41.0 million of lease revenue for the three months ended March 31, 2022 and 2021, respectively, and $79.8 million and $90.5 million during the six months ended March 31, 2022 and 2021, respectively. We have not separately stated aircraft rental income in the condensed consolidated statements of operations because the use of the aircraft is not a separate activity from the total service provided under our CPAs.

We have entered into lease agreements with GoJet Airlines LLC (“GoJet”) to lease 18 CRJ-700 aircraft as of March 31, 2022. The lease agreements are accounted for as operating leases and have a term of nine (9) years beginning on the delivery date of each aircraft. Under the lease agreements, GoJet pays fixed monthly rent per aircraft and variable lease payments for supplemental rent based on monthly aircraft utilization at fixed rates. Supplemental rent payments are subject to reimbursement following GoJet’s completion of qualifying maintenance events defined in the agreements. Lease revenue for fixed monthly rent payments is recognized ratably within contract revenue. Lease revenue for supplemental rent is deferred and recognized within contract revenue when it is probable that amounts received will not be reimbursed for future qualifying maintenance events over the lease term.

We mitigate the residual asset risks through supplemental rent payments and by leasing aircraft and engine types that we can operate in the event of a default. Additionally, the leases have specified lease return condition requirements and we maintain inspection rights under the leases. As of March 31, 2022, we recognized $14.7 million of lease incentive assets, net of amortization, and $11.5 million of related lease incentive obligations for reimbursement of certain aircraft maintenance costs defined within the lease agreements. Lease incentive assets are amortized on a straight-line basis and recognized as a reduction to lease revenue over the lease term.

Lease revenue recognized under the GoJet agreements, net of amortization of the lease incentive assets, was $6.8 million and $13.3 million for the three and six months ended March 31, 2022, respectively. Amounts deferred for supplemental rent payments totaled $1.9 million as of March 31, 2022.

The following table summarizes future minimum rental income under operating leases related to leased aircraft that had remaining non-cancelable lease terms as of March 31, 2022 (in thousands):

Periods Ending September 30,	Total Payments
2022 (remainder of)	$	9,828
2023		19,656
2024		19,656
2025		19,656
2026		19,656
Thereafter		72,474
Total	$	160,926

Leases

We determine if an arrangement is a lease at inception. As a lessee, we have lease agreements with lease and non-lease components and have elected to account for such components as a single lease component. Our operating lease activities are recorded in operating lease right-of-use assets, current maturities of operating leases, and noncurrent operating lease liabilities in the condensed consolidated balance sheets. Finance leases are reflected in property and equipment, net, current portion of long-term debt and finance leases, and long-term debt and finance leases, excluding current portion in the condensed consolidated balance sheets.

Right-of-use (“ROU”) assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. Certain variable lease payments are not included in the calculation of the right-of-use assets and lease liability due to uncertainty of the payment amount and are recorded as lease expense in the period incurred. In determining the present value of lease payments, we use either the implicit rate in the lease when it is readily determinable or our estimated incremental borrowing rate, based on information available at the lease commencement. Our lease terms include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Operating lease costs are recognized on a straight-line basis over the lease term, while finance leases result in a front-loaded expense pattern.

As a lessee, we have elected a short-term lease practical expedient on all classes of underlying assets, permitting us to not apply the recognition requirements of ASC 842 to leases with terms of 12 months or less.

We lease, at nominal rates, certain aircraft from United and DHL under our United CPA and DHL FSA, which are excluded from operating lease assets and liabilities as they do not represent embedded leases under ASC 842. Other than such leases at nominal amounts, approximately 11% of our aircraft are leased from third parties. All of our aircraft leases have been classified as operating leases, which results in rental payments being charged to expense over the term of the related leases. In the event that we or one of our major partners decide to exit an activity involving leased aircraft, losses may be incurred. In the event that we exit an activity that results in exit losses, these losses are accrued as each aircraft is removed from operations for early termination penalties, lease settle up and other charges. Additionally, any remaining ROU assets and lease liabilities are written off.

The majority of our leased aircraft are leased through trusts that have a sole purpose to purchase, finance, and lease these aircraft to us; therefore, they meet the criteria of a variable interest entity. However, since these are single-owner trusts in which we do not participate, we are not at risk for losses and are not considered the primary beneficiary. Management believes that our maximum exposure under these leases is the remaining lease payments.

Contract Liabilities

Contract liabilities consist of deferred credits for cost reimbursements from major partners related to aircraft modifications and pilot training associated with capacity purchase agreements. The deferred credits are recognized over time depicting the pattern of the transfer of control of services resulting in ratable recognition of revenue over the remaining term of the capacity purchase agreements.

Current and non-current deferred credits are recorded in other accrued expenses and non-current deferred credits in the condensed consolidated balance sheets. Our total current and non-current deferred credit balances at March 31, 2022 and September 30, 2021 were $4.4 million and $4.8 million, respectively. We recognized $0.2 million and $1.1 million of the deferred credits within contract revenue during the three months ended March 31, 2022 and 2021, respectively, and $0.4 million and $1.9 million during the six months ended March 31, 2022 and 2021, respectively.

Maintenance Expense

We operate under an FAA approved continuous inspection and maintenance program. The cost of non-major scheduled inspections and repairs and routine maintenance costs for all aircraft and engines are charged to maintenance expense as incurred.

We account for heavy maintenance and major overhaul costs on our owned E-175 fleet under the deferral method whereby the cost of heavy maintenance and major overhaul is deferred and amortized until the earlier of the end of the useful life of the related asset or the next scheduled heavy maintenance event. Amortization of heavy maintenance and major overhaul costs charged to depreciation and amortization expense was $0.4 million and $0.0 million for the three months ended March 31, 2022 and 2021, respectively, and $0.6 million and $0.0 million for the six months ended March 31, 2022 and 2021, respectively. As of March 31, 2022 and September 30, 2021, our deferred heavy maintenance balance, net of accumulated amortization, was $5.3 million and $3.5 million, respectively.

We account for heavy maintenance and major overhaul costs for all other fleets under the direct expense method whereby costs are expensed to maintenance expense as incurred, except for certain maintenance contracts where labor and materials price risks have been transferred to the service provider and require payment on a utilization basis, such as flight hours. Costs incurred for maintenance and repair for utilization maintenance contracts where labor and materials price risks have been transferred to the service provider are charged to maintenance expense based on contractual payment terms.

Engine overhaul expense totaled $4.8 million and $6.9 million for the three months ended March 31, 2022 and 2021, respectively, of which $4.6 million and $2.2 million, respectively, was pass-through expense. Engine overhaul expense totaled $10.1 million and $21.3 million for the six months ended March 31, 2022 and 2021, respectively, of which $8.4 million and $11.8 million, respectively, was pass-through expense. Airframe C-check expense totaled $4.7 million and $14.1 million for the three months ended March 31, 2022 and 2021, respectively, of which $0.5 million and $5.6 million, respectively, was pass-through expense. Airframe C-check expense totaled $13.8 million and $24.2 million for the six months ended March 31, 2022 and 2021, respectively, of which $0.5 million and $12.7 million, respectively, was pass-through expense.

Assets Held for Sale

We classify assets as held for sale when our management approves and commits to a formal plan of sale that is probable of being completed within one year. Assets designated as held for sale are recorded at the lower of their current carrying value or their fair market value, less costs to sell, beginning in the period in which the assets meet the criteria to be classified as held for sale. See Note 6 for further discussion of our assets classified as held for sale as of March 31, 2022.

Recent Accounting Pronouncements

6 Months Ended

Mar. 31, 2022

Accounting Changes And Error Corrections [Abstract]

Recent Accounting Pronouncements

3.	Recent Accounting Pronouncements

In December 2019, the FASB issued new guidance to simplify the accounting for income taxes by eliminating certain exceptions allowable under the existing guidance related to the approach for intraperiod tax allocations, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences. Our adoption of this guidance on October 1, 2021 did not have a material impact.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) (“ASU 2020-04”). This ASU provides optional expedients and exceptions for a limited period of time for accounting for contracts, hedging relationships, and other transactions affected by the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued. Optional expedients can be applied through December 31, 2022. We continue to evaluate our contracts that reference LIBOR.

- Definition

The entire disclosure for change in accounting principle. Includes, but is not limited to, nature, reason, and method of adopting amendment to accounting standards or other change in accounting principle.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Concentrations of Credit Risk

6 Months Ended

Mar. 31, 2022

Risks And Uncertainties [Abstract]

Concentrations of Credit Risk

4.	Concentrations of Credit Risk

Financial instruments that potentially expose the Company to a concentration of credit risk consist principally of cash and cash equivalents that are primarily held by financial institutions in the United States and accounts receivable. Amounts on deposit with a financial institution may at times exceed federally insured limits. We maintain our cash accounts with high credit quality financial institutions and, accordingly, minimal credit risk exists with respect to the financial institutions.

As of March 31, 2022, we had $3.4 million in restricted cash. We have an agreement with a financial institution for a letter of credit facility and to issue letters of credit for particular airport authorities, worker's compensation insurance, property and casualty insurance and other business needs as required in certain lease agreements. Pursuant to the terms of this agreement, $3.4 million of outstanding letters of credit are required to be collateralized by amounts on deposit.

Significant customers are those which represent more than 10% of our total revenue or net accounts receivable balance at each respective balance sheet date. All of our revenue for the three and six months ended March 31, 2022 and 2021 was derived from the American and United CPAs, DHL FSA, and from leases of our CRJ-700 aircraft to GoJet. Substantially all of our accounts receivable at March 31, 2022 and September 30, 2021 was derived from these agreements.

American accounted for approximately 46% and 45% of our total revenue for the three months ended March 31, 2022 and 2021, respectively, and 46% and 46% of our total revenue for the six months ended March 31, 2022 and 2021, respectively. United accounted for approximately 47% and 53% of our total revenue for the three months ended March 31, 2022 and 2021, respectively, and 48% and 52% of our total revenue for the six months ended March 31, 2022 and 2021, respectively. A termination of either the American or United CPA would have a material adverse effect on our business prospects, financial condition, results of operations, and cash flows.

Amounts billed under our agreements are subject to our interpretation of the applicable agreement and are subject to audit by our major partners. Periodically, our major partners dispute amounts billed and pay amounts less than the amount billed. Ultimate collection of the remaining amounts not only depends upon the Company prevailing under the applicable audit, but also upon the financial well-being of the major partner. As such, we review amounts due based on historical collection trends, the financial condition of the major partners, and current external market factors and record a reserve for amounts estimated to be uncollectible in accordance with the applicable guidance for expected credit losses. Our allowance for doubtful accounts was not material as of March 31, 2022 or September 30, 2021. If our ability to collect these receivables and the financial viability of our major partners is materially different than estimated, our estimate of the allowance for credit losses could be materially impacted.

Intangible Assets

6 Months Ended

Mar. 31, 2022

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets

5.	Intangible Assets

Information about our intangible assets as of March 31, 2022 and September 30, 2021, is as follows (in thousands):

	March 31,			September 30,
	2022			2021
Customer relationship	$	43,800		$	43,800
Accumulated amortization		(37,519	)		(37,008	)
Net carrying value	$	6,281		$	6,792

Total amortization expense recognized was $0.3 million and $0.3 million for the three months ended March 31, 2022 and 2021, respectively, and $0.5 million and $0.6 million for the six months ended March 31, 2022 and 2021, respectively. We expect to record amortization expense of $0.5 million for the remainder of 2022, and $0.9 million, $0.8 million, $0.7 million, and $0.6 million for fiscal years 2023, 2024, 2025 and 2026, respectively, and $2.8 million of amortization expense thereafter.

As of March 31, 2022, our intangible assets’ remaining weighted average term is 13.5 years.

Assets Held for Sale

6 Months Ended

Mar. 31, 2022

Discontinued Operations And Disposal Groups [Abstract]

Assets Held for Sale

6.	Assets Held for Sale

During the three months ended March 31, 2022, our management committed to a formal plan to sell certain of our CRJ-900 and CRJ-200 aircraft. The aircraft are expected to be disposed of via sale within the next 12 months. Accordingly, we determined the aircraft met the criteria to be classified as assets held for sale and have separately presented them in our condensed consolidated balance sheet at the lower of their current carrying value or their fair market value less costs to sell. The fair values are based upon observable and unobservable inputs, including recent purchase offers and market trends and conditions. The assumptions used to determine the fair value of our assets held for sale are subject to inherent uncertainty and could produce a wide range of outcomes which we will continue to monitor in future periods as new information becomes available. Prior to the ultimate sale of the assets, subsequent changes in our estimate of the fair value of our assets held for sale will be recorded as a gain or loss with a corresponding adjustment to the assets’ carrying value. In connection with the classification of these assets as held for sale, we recorded impairment losses of $39.5 million, which are reflected within impairment of assets held for sale in our condensed consolidated statements of operations and comprehensive loss.

Balance Sheet Information

6 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Balance Sheet Information

7.	Balance Sheet Information

Certain significant amounts included in the condensed consolidated balance sheets consisted of the following (in thousands):

	March 31,			September 30,
	2022			2021
Expendable parts and supplies, net:
Expendable parts and supplies	$	31,817		$	29,297
Less: obsolescence and other		(5,562	)		(4,830	)
	$	26,255		$	24,467
Prepaid expenses and other current assets:
Prepaid aviation insurance	$	2,236		$	2,171
Lease incentives		1,792			1,445
Other		3,580			3,269
	$	7,608		$	6,885
Property and equipment, net:
Aircraft and other flight equipment	$	1,507,441		$	1,611,544
Other equipment		5,369			4,934
Leasehold improvements		2,776			2,776
Vehicles		950			1,184
Building		699			699
Furniture and fixtures		298			300
Total property and equipment		1,517,533			1,621,437
Less: accumulated depreciation		(453,184	)		(469,546	)
	$	1,064,349		$	1,151,891
Other assets:
Investments in equity securities	$	19,904		$	25,149
Lease incentives		12,904			10,957
Other		65			15
	$	32,873		$	36,121
Other accrued expenses:
Accrued property taxes	$	3,940		$	8,783
Accrued interest		2,546			2,565
Accrued vacation		5,190			5,936
Other		19,730			16,373
	$	31,406		$	33,657
Other noncurrent liabilities:
Warrant liabilities	$	25,225		$	21,964
Lease incentive obligations		6,503			6,358
Other		4,666			6,269
	$	36,394		$	34,591

We record impairment charges on long-lived assets used in operations when events and circumstances indicate that the assets may be impaired, the undiscounted net cash flows estimated to be generated by those assets are less than the carrying amount of those assets, and the net book value of the assets exceeds their estimated fair value. We have assessed whether any impairment of our long-lived assets held and used existed and have determined that no charges were deemed necessary under applicable accounting standards as of March 31, 2022. Our assumptions about future conditions relevant to the assessment of potential impairment of our long-lived assets held and used are subject to uncertainty, and we will continue to monitor these conditions in future periods as new information becomes available, and will update our analyses accordingly.

Property and equipment, net:

Depreciation of property and equipment totaled $20.1 million and $20.4 million for the three months ended March 31, 2022 and 2021, respectively, and $40.6 million and $40.6 million for the six months ended March 31, 2022 and 2021, respectively.

Investments in Equity Securities

In connection with a negotiated forward purchase contract for electrically-powered vertical takeoff and landing aircraft (“eVTOL aircraft”) executed in February 2021, we obtained warrants giving us the right to acquire a number shares of common stock in Archer Aviation, Inc. (“Archer”). We estimated the initial equity warrant asset value to be $16.4 million based on publicly available information as of the grant date. In September 2021, the merger between Archer and a special purpose acquisition company (“SPAC”) was completed, resulting in a readily determinable fair value of our investments in Archer. Accordingly, gains and losses associated with changes in the fair value of our investments in Archer are measured in earnings, in accordance with ASC 321, Investments – Equity Securities. In connection with the closing of the merger between Archer and the SPAC, we purchased 500,000 Class A common shares in Archer for $5.0 million, and obtained an additional warrant to purchase shares of Archer with a total grant date value of $5.6 million. All of our vested warrants have been exercised into shares of Archer common stock.

The initial grant date values of the warrants were recognized as a vendor credit liability within other noncurrent liabilities. The liability related to the warrant assets will be settled in the future, as a reduction of the acquisition date value of the eVTOL aircraft contemplated in the related aircraft purchase agreement.

Our investments in Archer are classified as Level 1 within the fair value hierarchy as the values are determined using quoted prices for the equity securities.

In connection with a negotiated forward purchase contract for fully electric aircraft executed in July 2021, we obtained $5.0 million of preferred stock in Heart Aerospace Incorporated (“Heart”), a privately held company. Our investment in Heart does not have a readily determinable fair value, so we account for the investment using the measurement alternative under ASC 321 and measure the investment at initial cost less impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar investments from the same issuer. We consider a range of factors when adjusting the fair value of these investments, including, but not limited to, the term and nature of the investment, local market conditions, values for comparable securities, current and projected operating performance, financing transactions subsequent to the acquisition of the investment, or other features that indicate a change to fair value is warranted. Any changes in fair value from the initial cost of the investment in preferred stock are recognized as increases or decreases on our balance sheet and as net gains or losses on investments in equity securities. The initial investment in preferred stock was measured at cost of $5.0 million.

In connection with a negotiated forward purchase contract for hybrid-electric vertical takeoff and landing (“VTOL”) aircraft executed in February 2022, we obtained a warrant giving us the right to acquire a number of shares of common stock in the privately-held manufacturer of the VTOL aircraft. These investments do not have a readily determinable fair value, so we account for them using the measurement alternative under ASC 321 and measure the investments at cost less impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar investments from the same issuer. We consider a range of factors when adjusting the fair value of these investments, including, but not limited to, the term and nature of the investment, local market conditions, values for comparable securities, current and projected operating performance, financing transactions subsequent to the acquisition of the investment or other features that indicate a discount to fair value is warranted. Any changes in fair value from the grant date value of the warrant assets will be recognized as increases or decreases to the investment on our balance sheet and as net gains or losses on investments equity securities. We estimated the initial warrant asset value to be $3.2 million based on prices of similar investments in the same issuer. The grant date value of the warrants, $3.2 million, was recognized as a vendor credit liability within other noncurrent liabilities. The liability related to the warrant assets will be settled in the future, as a reduction of the acquisition date value of the VTOL aircraft contemplated in the related forward purchase agreement.

Total net losses on our investments in equity securities totaled $2.3 million and $8.7 million during the three and six months ended March 31, 2022, respectively, and are reflected in loss on investments, net in our condensed consolidated statement of operations. As of March 31, 2022, the aggregate carrying amount of our investments in equity securities was $19.9 million, and the carrying amount of our investments without readily determinable fair values was $9.0 million.

Fair Value Measurements

6 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

8.	Fair Value Measurements

Fair value is an exit price representing the amount that would be received to sell an asset, or paid to transfer a liability, in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Accounting standards include disclosure requirements relating to the fair values used for certain financial instruments and establish a fair value hierarchy. The hierarchy prioritizes valuation inputs into three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of three levels:

Level 1	—	Observable inputs such as quoted prices in active markets for identical assets or liabilities;
Level 2	—	Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and
Level 3	—	Unobservable inputs in which there is little or no market data, requiring an entity to develop its own assumptions.

Other than our assets held for sale and investments in equity securities described in Notes 6 and 7, respectively, we did not measure any of our assets or liabilities at fair value on a recurring or nonrecurring basis as of March 31, 2022 and September 30, 2021.

The carrying values reported in the condensed consolidated balance sheets for cash and cash equivalents, accounts receivable, and accounts payable approximate fair value because of the immediate or short-term maturity of these financial instruments.

Our debt agreements are not traded on an active market. We have determined the estimated fair value of our debt to be Level 3, as certain inputs used to determine the fair value of these agreements are unobservable and, therefore, could be sensitive to changes in inputs. We utilize the discounted cash flow method to estimate the fair value of Level 3 debt.

The carrying value and estimated fair value of our total long-term debt, including current maturities, were as follows (in millions):


	March 31, 2022				September 30, 2021
	Carrying		Fair		Carrying		Fair
	Value		Value		Value		Value
Long-term debt and finance leases, including current maturities⁽¹⁾	$	652.0	$	609.7	$	670.3	$	676.8

⁽¹⁾	Current and prior period long-term debts' carrying and fair values exclude net debt issuance costs.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Long-Term Debt, Finance Leases, and Other Borrowings

6 Months Ended

Mar. 31, 2022

Debt Disclosure [Abstract]

Long-Term Debt, Finance Leases and Other Borrowings

9.	Long-Term Debt, Finance Leases, and Other Borrowings

Long-term debt as of March 31, 2022 and September 30, 2021, consisted of the following (in thousands):

	March 31,			September 30,
	2022			2021
Senior and subordinated notes payable to secured parties, collateralized
by the underlying aircraft, due 2027⁽¹⁾		80,244			86,551
Notes payable to secured parties, collateralized by the underlying
aircraft, due 2028⁽²⁾		141,690			152,100
Senior and subordinated notes payable to secured parties, collateralized
by the underlying aircraft, due 2028⁽³⁾		114,883			122,762
Other obligations due to financial institution, collateralized by the underlying
equipment, due 2023⁽⁴⁾		3,448			4,581
Notes payable to financial institution, collateralized by the underlying
equipment, due 2024⁽⁵⁾		36,290			45,559
Notes payable to financial institution, collateralized by the underlying
aircraft, due 2023⁽⁶⁾		21,875			30,625
Notes payable to financial institution due 2023⁽⁷⁾		3,000			4,000
Revolving credit facility⁽⁸⁾		15,630			22,930
Notes payable to U.S. Treasury due 2025⁽⁹⁾		204,947			201,227
Notes payable to financial institution, collateralized by the underlying
equipment, due 2027⁽¹⁰⁾		29,943			—
Gross long-term debt, including current maturities		651,950			670,335
Less unamortized debt issuance costs		(10,368	)		(9,295	)
Less notes payable warrants		(8,454	)		(9,630	)
Net long-term debt, including current maturities		633,128			651,410
Less current portion, net of unamortized debt issuance costs		(111,671	)		(111,710	)
Net long-term debt	$	521,457		$	539,700

⁽¹⁾

In fiscal 2015, we financed seven CRJ-900 aircraft with $170.2 million in debt. The senior notes payable of $154.7 million bear interest at monthly LIBOR plus 2.71% and require monthly principal and interest payments. The subordinated notes payable are noninterest-bearing and become payable in full on the last day of the term of the notes. We imputed an interest rate of 6.25% on the subordinated notes payable and recorded a related discount of $8.1 million, which is being accreted to interest expense over the term of the notes.

⁽²⁾	In fiscal 2016, we financed ten E-175 aircraft with $246.0 million in debt under an EETC financing arrangement (see discussion below). The debt bears interest ranging from 4.75% to 6.25% and requires semi-annual principal and interest payments.

⁽³⁾

In fiscal 2016, we financed eight E-175 aircraft with $195.3 million in debt. The senior notes payable of $172.0 million bear interest at the three-month LIBOR plus a spread ranging from 2.20% to 2.32% and require quarterly principal and interest payments. The subordinated notes payable bear interest at 4.50% and require quarterly principal and interest payments.

⁽⁴⁾	In February 2018, we leased two spare engines. The leases were determined to be finance leases as the leases contain a bargain purchase option at the end of the term. Imputed interest is 9.128% and the leases require monthly payments.

⁽⁵⁾	In January 2019, we financed certain flight equipment with $91.2 million in debt. The debt bears interest at the monthly LIBOR plus 3.10% and requires monthly principal and interest payments.

⁽⁶⁾	In June 2019, we financed ten CRJ-700 aircraft with $70.0 million in debt, which were previously leased. The debt bears interest at the monthly LIBOR plus 5.00% and requires monthly principal and interest payments.

⁽⁷⁾	In September 2019, we financed certain flight equipment for $8.0 million. The debt bears interest at the monthly LIBOR plus 5.00% and requires monthly principal and interest payments.

⁽⁸⁾	In September 2019, we extended the term on our $35.0 million working capital draw loan by three years, which now terminates in September 2022. Interest is assessed on drawn amounts at one-month LIBOR plus 3.75%.

⁽⁹⁾

^{In October 2020, we entered into a loan and guarantee agreement with the U.S. Department of the Treasury for a secured loan facility of up to $200.0 million that matures on October 30, 2025. On October 30, 2020, we borrowed $43.0 million and on November 13, 2020, we borrowed an additional $152.0 million. These amounts bear interest at the three-month LIBOR plus 3.50%. No further borrowings are available under the loan and guarantee agreement.}

⁽¹⁰⁾

In December 2021, we financed the purchase of spare engines with $30.8 million in debt. The debt bears interest at monthly LIBOR plus 4.25% and requires monthly principal and interest payments over a term of six years. The financing arrangement allows for additional borrowings to finance future engine purchases.

Principal maturities of long-term debt as of March 31, 2022, and for each of the next five years are as follows (in thousands):

Periods Ending September 30,	Total Principal
2022 (remainder of)	$	64,018
2023		94,670
2024		66,417
2025		61,734
2026		268,972
Thereafter		96,139
	$	651,950

The carrying value of collateralized aircraft and equipment as of March 31, 2022 was $1,029.7 million.

Enhanced Equipment Trust Certificate ("EETC")

In December 2015, an Enhanced Equipment Trust Certificate ("EETC") pass-through trust was created to issue pass-through certificates to obtain financing for new E-175 aircraft. As of March 31, 2022, we had $141.7 million of equipment notes outstanding issued under the EETC financing included in long-term debt in the condensed consolidated balance sheets. The structure of the EETC financing consists of a pass-through trust created by Mesa to issue pass-through certificates, which represent fractional undivided interests in the pass-through trust and are not obligations of Mesa.

The proceeds of the issuance of the pass-through certificates were used to purchase equipment notes which were issued by Mesa and secured by its aircraft. The payment obligations under the equipment notes are those of Mesa. Proceeds received from the sale of pass-through certificates were initially held by a depositary in escrow for the benefit of the certificate holders until Mesa issued equipment notes to the trust, which purchased such notes with a portion of the escrowed funds.

We evaluated whether the pass-through trust formed for the EETC financing is a Variable Interest Entity ("VIE") and required to be consolidated. We have determined we do not have a variable interest in the pass-through trust, and therefore, we have not consolidated the pass-through trust with our financial statements.

CIT Revolving Credit Facility

On September 25, 2019, we extended the term on our $35.0 million working capital draw loan by three years, which now terminates in September 2022. Interest is assessed on drawn amounts at one-month LIBOR plus 3.75%. As of March 31, 2022, the amount outstanding on the working capital draw loan was $15.6 million.

Our CIT revolving credit facility includes a minimum interest and rental coverage ratio covenant. In March and April 2022, we entered into amendments to the CIT revolving credit facility which lowered the minimum interest and rental coverage ratio covenant for the December 2021, March 2022, and June 2022 quarters. As a result, we are in compliance with this covenant.

Loan Agreement with the United States Department of the Treasury

On October 30, 2020, we entered into a loan and guarantee agreement with the U.S. Department of the Treasury (the “U.S. Treasury”) for a secured loan facility of up to $200.0 million that matures in October 2025 (“the Treasury Loan”). During the first quarter of fiscal 2021, we borrowed an aggregate of $195.0 million. No further borrowings are available under the Treasury Loan.

The Treasury Loan bears interest at a variable rate equal to (a)(i) the LIBOR rate divided by (ii) one minus the Eurodollar Reserve Percentage plus (b) 3.50%. Accrued interest on the loans is payable in arrears, or paid-in-kind by increasing the principal balance of the loan by such interest payment, on the first business day following the 14^th day of each March, June, September, and December.

All principal amounts outstanding under the Treasury Loan are due and payable in a single installment on October 30, 2025. Through March 31, 2022, interest on the Treasury Loan has been paid-in-kind by increasing the principal amount of the loan by the amount of such interest due on the interest payment date. Our obligations under the Treasury Loan are secured by certain aircraft, aircraft engines, accounts receivable, ground service equipment, flight simulators, and tooling (collectively, the “Collateral”). The obligations under the Treasury Loan are guaranteed by the Company and Mesa Air Group Inventory Management. The proceeds were used for general corporate purposes and operating expenses, to the extent permitted by the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). Voluntary prepayments of the Treasury Loan may be made, in whole or in part, without premium or penalty, at any time and from time to time. Amounts prepaid may not be reborrowed. Mandatory prepayments of the Treasury Loan are required, without premium or penalty, to the extent necessary to comply with the covenants discussed below, certain dispositions of the Collateral, certain debt issuances secured by liens on the Collateral, and certain insurance payments related to the Collateral. In addition, if a “change of control” (as defined in the Treasury Loan) occurs with respect to Mesa Airlines, we will be required to repay the loans outstanding under the Treasury Loan.

The Treasury Loan requires us, under certain circumstances, including within ten (10) business days prior to the last business day of March and September of each year beginning March 2021, to appraise the value of the Collateral and recalculate the collateral coverage ratio. If the calculated collateral coverage ratio is less than 1.6 to 1.0, we are required either to provide additional Collateral (which may include cash collateral) to secure the obligations under the Treasury Loan or repay the term loans under the Treasury Loan, in such amounts that the recalculated collateral coverage ratio, after giving effect to any such additional Collateral or repayment, is at least 1.6 to 1.0.

The Treasury Loan contains two financial covenants, a minimum collateral coverage ratio and a minimum liquidity level. The Treasury Loan also contains customary negative and affirmative covenants for credit facilities of this type, including, among others: (a) limitations on dividends and distributions; (b) limitations on the creation of certain liens; (c) restrictions on certain dispositions, investments, and acquisitions; (d) limitations on transactions with affiliates; (e) restrictions on fundamental changes to the business, and (f) restrictions on lobbying activities. Additionally, we are required to comply with the relevant provisions of the CARES Act, including limits on employment level reductions after September 30, 2020, restrictions on dividends and stock buybacks, limitations on executive compensation, and requirements to maintain certain levels of scheduled service.

In connection with the Treasury Loan and as partial compensation to the U.S. Treasury for the provision of financial assistance under the Treasury Loan, we issued to the U.S. Treasury warrants to purchase an aggregate of 4,899,497 shares of our common stock at an exercise price of $3.98 per share, which was the closing price of the common stock on April 9, 2020. The exercise price and number of shares of common stock issuable under the warrants are subject to adjustment as a result of anti-dilution provisions contained in the warrants for certain stock issuances, dividends, and other corporate actions. The warrants expire on the fifth anniversary of the date of issuance and are exercisable either through net share settlement or net cash settlement, at our option. The fair value of the warrants was estimated using a Black-Scholes option pricing model and recorded in stockholders' equity with an offsetting debt discount to the Treasury Loan in the condensed consolidated balance sheet.

In April 2022, we entered into an agreement with the U.S. Treasury to lower the minimum collateral coverage ratio covenant to 1.5 to 1.0 through September 30, 2022. As a result, we are in compliance with this covenant as of March 31, 2022.

Spare Engine Financing

In December 2021, we entered into a loan agreement with a financing institution to finance certain purchases of spare engines via a newly-formed limited liability company (“LLC”). The loan agreement provides for aggregate borrowings of up to $54.0 million through November 2022. In December 2021, we borrowed an aggregate of $30.8 million under the loan agreement, which matures in December 2027. The borrowed amounts are collateralized by the underlying engines and require monthly principal and interest payments until maturity. Borrowings under the loan agreement bear interest at the monthly LIBOR plus 4.25%. The borrowings are the obligation of the newly-formed LLC and are guaranteed by Mesa Airlines, Inc.

The newly-formed LLC, which is wholly-owned by Mesa, was determined to be a VIE for which we are the primary beneficiary because we have the power to direct the activities of the LLC that most significantly impact the LLC’s economic performance and the obligation to absorb losses and right to receive benefits from the LLC in our capacity as sole member of the LLC and guarantor of the borrowings. Therefore, this entity is consolidated in our financial statements and the borrowings are reflected as long-term debt in our condensed consolidated balance sheet.

The loan agreement contains a loan-to-value (“LTV”) financial covenant pursuant to which we are required to prepay certain amounts of the loan if the aggregate outstanding principal balance of the loan exceeds a specified percentage of the appraised value of the engines beginning in the 12^th full month after closing and each June 1 and December 1 thereafter.

As of March 31, 2022, we were in compliance with all debt covenants.

Earnings Per Share

6 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Earnings Per Share

10.	Earnings Per Share

Calculations of net income (loss) per common share attributable to Mesa Air Group were as follows (in thousands, except per share data):

	Three Months Ended March 31,					Six Months Ended March 31,
	2022			2021		2022			2021
Net income (loss) attributable to Mesa Air Group	$	(42,783	)	$	5,689	$	(57,057	)	$	19,807
Basic weighted average common shares outstanding		36,048			35,628		36,005			35,579
Add: Incremental shares for:
Dilutive effect of warrants		—			3,038		—			2,183
Dilutive effect of restricted stock		—			766		—			620
Diluted weighted average common shares outstanding		36,048			39,432		36,005			38,382
Net income (loss) per common share attributable to Mesa Air Group:
Basic	$	(1.19	)	$	0.16	$	(1.58	)	$	0.56
Diluted	$	(1.19	)	$	0.14	$	(1.58	)	$	0.52

Basic income or loss per common share is computed by dividing net income or loss attributable to Mesa Air Group by the weighted average number of common shares outstanding during the period.

The number of incremental shares from the assumed issuance of shares relating to restricted stock and exercise of warrants is calculated by applying the treasury stock method. Share-based awards and warrants whose impact is anti-dilutive under the treasury stock method are excluded from the diluted net income or loss per share calculation. In loss periods, these incremental shares are excluded from the calculation of diluted loss per share, as the inclusion of unvested restricted stock and warrants would have an anti-dilutive effect.

The following number of weighted-average potentially dilutive shares were excluded from the calculation of diluted net income (loss) per share because the effect of including such potentially dilutive shares would have been anti-dilutive:

	Three Months Ended March 31,				Six Months Ended March 31,
	2022		2021		2022		2021
Warrants		818		—		1,671		—
Restricted stock		84		—		235		—
		902		—		1,906		—

Common Stock

6 Months Ended

Mar. 31, 2022

Stockholders Equity Note [Abstract]

Common Stock

11.	Common Stock

As discussed in Note 9, we issued warrants to the U.S. Treasury to purchase shares of our common stock, no par value, at an exercise price of $3.98 per share. The exercise price and number of shares issuable under the warrants are subject to adjustment as a result of anti-dilution provisions contained in the warrants for certain stock issuances, dividends, and other corporate actions. The warrants expire on the fifth anniversary of the date of issuance and are exercisable either through net share settlement or net cash settlement, at our option. The warrants were accounted for within equity at a grant date fair value determined under the Black-Scholes option pricing model. As of March 31, 2022, 4,899,497 warrants were issued and outstanding.

We have not historically paid dividends on shares of our common stock. Additionally, the Treasury Loan and our aircraft lease facility with RASPRO Trust 2005, a pass-through trust, contain restrictions that limit our ability to or prohibit us from paying dividends to holders of our common stock.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

Income Taxes

6 Months Ended

Mar. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

12.	Income Taxes

Our effective tax rate (ETR) from continuing operations was 22.4% and 22.4% for the three and six months ended March 31, 2022, respectively, and 24.9% and 25.3% for the three and six months ended March 31, 2021, respectively. Our ETR during the three and six months ended March 31, 2022 was different from the prior year tax rates primarily as a result of vesting of stock compensation, changes in the valuation allowance against state net operating losses, and changes in state statutory rates. For the six months ended March 31, 2022, we used the year-to-date effective tax rate method to determine the interim income tax benefit because a reliable estimate of the annual effective tax rate could not be made.

We continue to maintain a valuation allowance on a portion of our state net operating losses in jurisdictions with shortened carryforward periods or in jurisdictions where our operations have significantly decreased as compared to prior years in which the net operating losses were generated.

As of September 30, 2021, we had aggregate federal and state net operating loss carryforwards of approximately $541.3 million and $235.7 million, respectively, which expire in fiscal years 2027-2038 and 2022-2041, respectively. Approximately $1.2 million of state net operating loss carryforwards are expected to expire in the current fiscal year.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Share-Based Compensation and Stock Repurchases

6 Months Ended

Mar. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation and Stock Repurchases

13.	Share-Based Compensation and Stock Repurchases

Restricted Stock

We grant restricted stock units (“RSUs”) as part of our long-term incentive compensation to employees and non-employee members of the Board of Directors. RSUs generally vest over a period of 3 to 5 years for employees and one year for members of the Board of Directors. The restricted common stock underlying RSUs are not deemed issued or outstanding upon grant, and do not carry any voting rights.

The restricted share activity for the six months ended March 31, 2022 is summarized as follows:

				Weighted-
				Average
	Number			Grant Date
	of Shares			Fair Value
Restricted shares unvested at September 30, 2021		1,006,206		$	6.22
Granted		187,993			4.72
Vested		(130,094	)		7.10
Forfeited		(28,695	)		10.08
Restricted shares unvested at March 31, 2022		1,035,410		$	5.73

As of March 31, 2022, there was $4.3 million of total unrecognized compensation cost related to unvested share-based compensation arrangements, which is expected to be recognized over a weighted-average period of 1.6 years.

Compensation cost for share-based awards is recognized on a straight-line basis over the vesting period. Share-based compensation expense for the three months ended March 31, 2022 and 2021 was $0.7 million and $0.8 million, respectively, and for the six months ended March 31, 2022 and 2021 was $1.4 million and $1.7 million, respectively.

We repurchased 15,696 shares of our common stock for $0.1 million to cover the income tax obligation on vested employee equity awards during the six months ended March 31, 2022.

Employee Stock Purchase Plan

6 Months Ended

Mar. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Employee Stock Purchase Plan

14.	Employee Stock Purchase Plan

2019 ESPP

The Mesa Air Group, Inc. 2019 Employee Stock Purchase Plan (the "2019 ESPP”) is a nonqualified plan that provides eligible employees of Mesa Air Group, Inc. with an opportunity to purchase Mesa Air Group, Inc. ordinary shares through payroll deductions. Under the 2019 ESPP, eligible employees may elect to contribute 1% to 15% of their eligible compensation during each semi-annual offering period to purchase Mesa Air Group, Inc. ordinary shares at a 10% discount.

A maximum of 500,000 Mesa Air Group, Inc. ordinary shares may be issued under the 2019 ESPP. As of March 31, 2022, eligible employees purchased and we issued an aggregate of 247,761 Mesa Air Group, Inc. ordinary shares under the 2019 ESPP, 53,567 of which were purchased and issued during the three and six months ended March 31, 2022.

Leases

6 Months Ended

Mar. 31, 2022

Leases [Abstract]

Leases

15.

Leases

As of March 31, 2022, we leased 18 aircraft, airport facilities, office space, and other property and equipment under non-cancelable operating leases. The leases generally require us to pay all taxes, maintenance, insurance, and other operating expenses. Rental expense is recognized on a straight-line basis over the lease term, net of lessor rebates and other incentives. We expect that, in the normal course of business, such operating leases that expire will be renewed or replaced by other leases, or the property may be purchased rather than leased.

Aggregate rental expense under all operating aircraft, equipment and facility leases totaled approximately $11.0 million and $11.3 million for the three months ended March 31, 2022 and 2021, respectively, and $22.2 million and $22.7 million for the six months ended March 31, 2022 and 2021, respectively.

The components of our operating lease costs were as follows (in thousands):

	Three Months Ended March 31,				Six Months Ended March 31,
	2022		2021		2022		2021
Operating lease costs	$	9,663	$	9,697	$	19,144	$	19,405
Variable and short-term lease costs		1,346		1,646		3,081		3,335
Total lease costs	$	11,009	$	11,343	$	22,225	$	22,740

As of March 31, 2022, our operating leases have a remaining weighted average lease term of 3.7 years and our operating lease liabilities were measured using a weighted average discount rate of 4.4%.

During the three and six months ended March 31, 2022, we recorded a $0.4 million impairment of certain operating lease ROU assets associated with the abandonment of a leased facility.

Commitments and Contingencies

6 Months Ended

Mar. 31, 2022

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

16.	Commitments and Contingencies

Engine Purchase Commitments

On February 26, 2021, the Company and General Electric Company (“GE”), acting through its GE-Aviation business unit, entered into an Amended and Restated Letter Agreement No. 13-3. We agreed to purchase and take delivery of ten (10) new CF34-8C5 or CF34-8E5 engines with delivery dates starting from July 1, 2021 through November 1, 2022. The total purchase commitment related to these ten (10) engines is approximately $52.2 million. We also have options to purchase an additional ten (10) similar engines beyond 2022. As of March 31, 2022, we have purchased five of the engines pursuant to the Amended and Restated Letter Agreement No. 13-3 with delivery of the remaining five (5) engines expected to take place during calendar year 2022.

If we fail to accept delivery of the spare engines when duly tendered, we may be assessed a minimum cancellation charge based on the engine price determined as of the date of scheduled engine delivery.

Litigation

We are subject to two putative class action lawsuits alleging federal securities law violations in connection with our IPO, one in the Superior Court of the State of Arizona and one in U.S. District Court of Arizona. These purported class actions were filed in March and April 2020 against the Company, certain current and former officers and directors, and certain underwriters of the Company’s IPO. The state and federal lawsuits each make the same or similar allegations of violations of the Securities Act of 1933, as amended, for allegedly making materially false and misleading statements in, or omitting material information from, our IPO registration statement. The plaintiffs seek unspecified monetary damages and other relief.

On March 2, 2022, the parties in the federal lawsuit attended a mediation and reached an agreement in principle to settle all claims asserted in that action for the sum of $5.0 million, which will be paid by the Company’s directors’ and officers’ insurance carriers. The settlement is subject to final documentation and preliminary and final approval by the federal court. The motion for preliminary approval must be filed on or before May 9, 2022. If preliminary and final approval is obtained, the claims of all putative class members, whether asserted in the federal or state actions, will be extinguished, unless and only to the extent that a particular class member takes affirmative steps to have its claims excluded.

In addition, we are subject to certain legal actions which we consider routine to our business activities.

We are involved in various legal proceedings (including, but not limited to, insured claims) and FAA civil action proceedings that we do not believe will have a material adverse effect upon our business, financial condition, or results of operations, although no assurance can be given to the ultimate outcome of any such proceedings.

Electric Aircraft Forward Purchase Commitments

As described in Note 7, in February 2021, we entered into a forward purchase contract with Archer for a number of eVTOL aircraft. The aggregate base commitment for the eVTOL aircraft is $200.0 million, with an option to purchase additional aircraft. Our obligation to purchase the eVTOL aircraft is subject to the Company and Archer first agreeing in the future to a number of terms and conditions, which may or may not be met.

As described in Note 7, in July 2021, we entered into a forward purchase contract with Heart for a number of fully electric aircraft. The maximum aggregate base commitment for the aircraft is $1,200.0 million, with an option to purchase additional aircraft. Our obligation to purchase the aircraft is subject to the Company and Heart first agreeing in the future to a number of terms and conditions, which may or may not be met.

Other Commitments

We have certain contracts for goods and services that require us to pay a penalty, acquire inventory specific to us or purchase contract-specific equipment, as defined by each respective contract, if we terminate the contract without cause prior to its expiration date. Because these obligations are contingent on our termination of the contract without cause prior to its expiration date, no obligation would exist unless such a termination occurs.

Subsequent Events

6 Months Ended

Mar. 31, 2022

Subsequent Events [Abstract]

Subsequent Events

17.	Subsequent Events

As described in Note 9, in April 2022 we entered into an agreement with the U.S. Treasury to lower the minimum collateral coverage ratio covenant to 1.5 to 1.0 through September 30, 2022.

As described in Note 9, in April 2022 we entered into an amendment to the CIT revolving credit facility which lowered the minimum financial ratio covenant for the March 2022 and June 2022 quarters.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Basis of Presentation

Segment Reporting

Use of Estimates

Contract Revenue and Pass-through and Other Revenue

Periods Ending September 30,	Total Revenue
2022 (remainder of)	$	714
2023		5,051
2024		9,330
2025		6,253
2026		3,673
Thereafter		4,522
Total	$	29,543

The following table summarizes future minimum rental income under operating leases related to leased aircraft that had remaining non-cancelable lease terms as of March 31, 2022 (in thousands):

Periods Ending September 30,	Total Payments
2022 (remainder of)	$	9,828
2023		19,656
2024		19,656
2025		19,656
2026		19,656
Thereafter		72,474
Total	$	160,926

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Schedule of Deferred Revenue Remaining Performance Obligations

Periods Ending September 30,	Total Revenue
2022 (remainder of)	$	714
2023		5,051
2024		9,330
2025		6,253
2026		3,673
Thereafter		4,522
Total	$	29,543

Schedule of Future Minimum Rental Income under Non-cancelable Operating Leases

The following table summarizes future minimum rental income under operating leases related to leased aircraft that had remaining non-cancelable lease terms as of March 31, 2022 (in thousands):

Periods Ending September 30,	Total Payments
2022 (remainder of)	$	9,828
2023		19,656
2024		19,656
2025		19,656
2026		19,656
Thereafter		72,474
Total	$	160,926

Intangible Assets (Tables)

6 Months Ended

Mar. 31, 2022

Goodwill And Intangible Assets Disclosure [Abstract]

Information About Intangible Assets

Information about our intangible assets as of March 31, 2022 and September 30, 2021, is as follows (in thousands):

	March 31,			September 30,
	2022			2021
Customer relationship	$	43,800		$	43,800
Accumulated amortization		(37,519	)		(37,008	)
Net carrying value	$	6,281		$	6,792

Balance Sheet Information (Tables)

6 Months Ended

Mar. 31, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Certain Significant Amounts Included in Condensed Consolidated Balance Sheet

Certain significant amounts included in the condensed consolidated balance sheets consisted of the following (in thousands):

	March 31,			September 30,
	2022			2021
Expendable parts and supplies, net:
Expendable parts and supplies	$	31,817		$	29,297
Less: obsolescence and other		(5,562	)		(4,830	)
	$	26,255		$	24,467
Prepaid expenses and other current assets:
Prepaid aviation insurance	$	2,236		$	2,171
Lease incentives		1,792			1,445
Other		3,580			3,269
	$	7,608		$	6,885
Property and equipment, net:
Aircraft and other flight equipment	$	1,507,441		$	1,611,544
Other equipment		5,369			4,934
Leasehold improvements		2,776			2,776
Vehicles		950			1,184
Building		699			699
Furniture and fixtures		298			300
Total property and equipment		1,517,533			1,621,437
Less: accumulated depreciation		(453,184	)		(469,546	)
	$	1,064,349		$	1,151,891
Other assets:
Investments in equity securities	$	19,904		$	25,149
Lease incentives		12,904			10,957
Other		65			15
	$	32,873		$	36,121
Other accrued expenses:
Accrued property taxes	$	3,940		$	8,783
Accrued interest		2,546			2,565
Accrued vacation		5,190			5,936
Other		19,730			16,373
	$	31,406		$	33,657
Other noncurrent liabilities:
Warrant liabilities	$	25,225		$	21,964
Lease incentive obligations		6,503			6,358
Other		4,666			6,269
	$	36,394		$	34,591

Fair Value Measurements (Tables)

6 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Carrying Value and Estimated Fair Value of Long-term Debt, Including Current Matur

The carrying value and estimated fair value of our total long-term debt, including current maturities, were as follows (in millions):


	March 31, 2022				September 30, 2021
	Carrying		Fair		Carrying		Fair
	Value		Value		Value		Value
Long-term debt and finance leases, including current maturities⁽¹⁾	$	652.0	$	609.7	$	670.3	$	676.8

⁽¹⁾	Current and prior period long-term debts' carrying and fair values exclude net debt issuance costs.

Long-Term Debt, Finance Leases, and Other Borrowings (Tables)

6 Months Ended

Mar. 31, 2022

Debt Disclosure [Abstract]

Schedule of Long-term Debt

Long-term debt as of March 31, 2022 and September 30, 2021, consisted of the following (in thousands):

	March 31,			September 30,
	2022			2021
Senior and subordinated notes payable to secured parties, collateralized
by the underlying aircraft, due 2027⁽¹⁾		80,244			86,551
Notes payable to secured parties, collateralized by the underlying
aircraft, due 2028⁽²⁾		141,690			152,100
Senior and subordinated notes payable to secured parties, collateralized
by the underlying aircraft, due 2028⁽³⁾		114,883			122,762
Other obligations due to financial institution, collateralized by the underlying
equipment, due 2023⁽⁴⁾		3,448			4,581
Notes payable to financial institution, collateralized by the underlying
equipment, due 2024⁽⁵⁾		36,290			45,559
Notes payable to financial institution, collateralized by the underlying
aircraft, due 2023⁽⁶⁾		21,875			30,625
Notes payable to financial institution due 2023⁽⁷⁾		3,000			4,000
Revolving credit facility⁽⁸⁾		15,630			22,930
Notes payable to U.S. Treasury due 2025⁽⁹⁾		204,947			201,227
Notes payable to financial institution, collateralized by the underlying
equipment, due 2027⁽¹⁰⁾		29,943			—
Gross long-term debt, including current maturities		651,950			670,335
Less unamortized debt issuance costs		(10,368	)		(9,295	)
Less notes payable warrants		(8,454	)		(9,630	)
Net long-term debt, including current maturities		633,128			651,410
Less current portion, net of unamortized debt issuance costs		(111,671	)		(111,710	)
Net long-term debt	$	521,457		$	539,700

⁽¹⁾

⁽²⁾	In fiscal 2016, we financed ten E-175 aircraft with $246.0 million in debt under an EETC financing arrangement (see discussion below). The debt bears interest ranging from 4.75% to 6.25% and requires semi-annual principal and interest payments.

⁽³⁾

⁽⁴⁾	In February 2018, we leased two spare engines. The leases were determined to be finance leases as the leases contain a bargain purchase option at the end of the term. Imputed interest is 9.128% and the leases require monthly payments.

⁽⁵⁾	In January 2019, we financed certain flight equipment with $91.2 million in debt. The debt bears interest at the monthly LIBOR plus 3.10% and requires monthly principal and interest payments.

⁽⁶⁾	In June 2019, we financed ten CRJ-700 aircraft with $70.0 million in debt, which were previously leased. The debt bears interest at the monthly LIBOR plus 5.00% and requires monthly principal and interest payments.

⁽⁷⁾	In September 2019, we financed certain flight equipment for $8.0 million. The debt bears interest at the monthly LIBOR plus 5.00% and requires monthly principal and interest payments.

⁽⁸⁾	In September 2019, we extended the term on our $35.0 million working capital draw loan by three years, which now terminates in September 2022. Interest is assessed on drawn amounts at one-month LIBOR plus 3.75%.

⁽⁹⁾

⁽¹⁰⁾

Schedule of Principal Maturities of Long-term Debt

Principal maturities of long-term debt as of March 31, 2022, and for each of the next five years are as follows (in thousands):

Periods Ending September 30,	Total Principal
2022 (remainder of)	$	64,018
2023		94,670
2024		66,417
2025		61,734
2026		268,972
Thereafter		96,139
	$	651,950

Earnings Per Share (Tables)

6 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Calculations of Net Income (Loss) Per Common Share

Calculations of net income (loss) per common share attributable to Mesa Air Group were as follows (in thousands, except per share data):

	Three Months Ended March 31,					Six Months Ended March 31,
	2022			2021		2022			2021
Net income (loss) attributable to Mesa Air Group	$	(42,783	)	$	5,689	$	(57,057	)	$	19,807
Basic weighted average common shares outstanding		36,048			35,628		36,005			35,579
Add: Incremental shares for:
Dilutive effect of warrants		—			3,038		—			2,183
Dilutive effect of restricted stock		—			766		—			620
Diluted weighted average common shares outstanding		36,048			39,432		36,005			38,382
Net income (loss) per common share attributable to Mesa Air Group:
Basic	$	(1.19	)	$	0.16	$	(1.58	)	$	0.56
Diluted	$	(1.19	)	$	0.14	$	(1.58	)	$	0.52

Number of Weighted-Average Potentially Dilutive Shares Excluded from Calculation of Diluted Net Income (Loss) Per Share

	Three Months Ended March 31,				Six Months Ended March 31,
	2022		2021		2022		2021
Warrants		818		—		1,671		—
Restricted stock		84		—		235		—
		902		—		1,906		—

Share-Based Compensation and Stock Repurchases (Tables)

6 Months Ended

Mar. 31, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Restricted Share Activity

The restricted share activity for the six months ended March 31, 2022 is summarized as follows:

				Weighted-
				Average
	Number			Grant Date
	of Shares			Fair Value
Restricted shares unvested at September 30, 2021		1,006,206		$	6.22
Granted		187,993			4.72
Vested		(130,094	)		7.10
Forfeited		(28,695	)		10.08
Restricted shares unvested at March 31, 2022		1,035,410		$	5.73

Leases (Tables)

6 Months Ended

Mar. 31, 2022

Leases [Abstract]

Components of Operating Lease Costs

The components of our operating lease costs were as follows (in thousands):

	Three Months Ended March 31,				Six Months Ended March 31,
	2022		2021		2022		2021
Operating lease costs	$	9,663	$	9,697	$	19,144	$	19,405
Variable and short-term lease costs		1,346		1,646		3,081		3,335
Total lease costs	$	11,009	$	11,343	$	22,225	$	22,740

Organization and Operations - Additional Information (Detail)		6 Months Ended
	Dec. 20, 2019 Air-craft	Mar. 31, 2022 Daily_Departure State Air-craft City Employee
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of states in which entity operates \| State		40
Number of aircrafts operated		168
Number of cities in which entity operates \| City		110
Number of daily departures \| Daily_Departure		349
Number of employees \| Employee		2,800
Number of aircrafts withdrawable on conditions		1
United capacity purchase agreement termination notice period		30 days
American Capacity Purchase Agreement [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Maximum number of aircraft withdraw in twenty twenty one		10
Maximum number of aircraft withdraw in twenty twenty two		5
Maximum number of aircraft withdraw in twenty twenty three		5
Aircrafts able to be withdrawn in future under normal withdrawal rights		20
Aircrafts able to be withdrawn in future, thereafter under normal withdrawal rights		20
American Capacity Purchase Agreement [Member] \| CRJ-900 Aircraft [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of aircrafts operated		40
United Capacity Purchase Agreement [Member] \| E-175 Aircraft [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of aircrafts operated		60
United Capacity Purchase Agreement [Member] \| E-175 Aircraft [Member] \| United [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of aircrafts operated		42
Lease expiration year		2028
Notice period for termination of agreement		United, subject to certain conditions, including the payment of certain costs tied to aircraft type, may terminate the agreement in its discretion, or remove E-175 aircraft from service, by giving us notice of 90 days or more
United Capacity Purchase Agreement [Member] \| E-175 Aircraft [Member] \| United [Member] \| Minimum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Lease expiration year		2024
United Capacity Purchase Agreement [Member] \| E-175 Aircraft [Member] \| United [Member] \| Maximum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Lease expiration year		2028
United Capacity Purchase Agreement [Member] \| E175LL Aircraft [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of aircrafts operated		20
Air crafts expiring month and year description		expiring between 2032 and 2033
United Capacity Purchase Agreement [Member] \| E175LL Aircraft [Member] \| United [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Notice period for termination of agreement		Commencing five (5) years after the actual in-service date, United has the right to remove the E-175 aircraft from service by giving us notice of 90 days or more, subject to certain conditions, including the payment of certain wind-down expenses plus, if removed prior to the ten (10) year anniversary of the in-service date, certain accelerated margin payments
United Capacity Purchase Agreement [Member] \| CRJ-700 Aircraft [Member] \| United [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of aircrafts operated		20
Aircraft lease term		9 years
Number of aircraft leased		18
DHL Flight Services Agreement [Member] \| Boeing 737400F [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of aircrafts operated	2
Aircraft lease term	5 years
Number of aircraft leased	2
Notice period for termination of agreement		At any time after the first anniversary of the commencement date of the first aircraft placed in service with 90 days’ written notice
Aircraft option to extend agreement description		DHL has the option to extend the agreement with respect to one or more aircraft for a period of one year with 90 days’ advance written notice.

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2022 USD ($) Air-craft	Mar. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue	$ 0.8		$ 5.0
Lease incentive assets	14.7		14.7
Lease incentive obligations	11.5		11.5
Amounts deferred for supplemental rent payments	1.9		1.9
Current and non-current deferred credit contract liability balances	4.4		4.4		$ 4.8
Recognized deferred credits within contract revenue	0.2	$ 1.1	0.4	$ 1.9
Amortization of heavy maintenance and major overhaul costs charged to depreciation and amortization expense	0.4	0.0	0.6	0.0
Deferred heavy maintenance balance, net of accumulated amortization	5.3		5.3		$ 3.5
Engine overhaul expense	4.8	6.9	10.1	21.3
Engine overhaul pass-through expense	4.6	2.2	8.4	11.8
Airframe check expense	4.7	14.1	13.8	24.2
Airframe check pass-through expense	0.5	5.6	$ 0.5	12.7
Aircraft [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage leased			11.00%
GoJet Agreements [Member]
Summary Of Significant Accounting Policies [Line Items]
Lease revenue recognized	$ 6.8		$ 13.3
CRJ 700 [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of aircraft to be leased \| Air-craft			18
Operating lease, term of contract	9 years		9 years
Contract Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Lease revenue	$ 39.5	$ 41.0	$ 79.8	$ 90.5

Summary of Significant Accounting Policies - Schedule of Deferred Revenue Remaining Performance Obligations (Detail) $ in Thousands	Mar. 31, 2022 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 29,543
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-04-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 714
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 5,051
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 9,330
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2024-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 6,253
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 3,673
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Revenue	$ 4,522
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year

Summary of Significant Accounting Policies - Schedule of Deferred Revenue Remaining Performance Obligations (Detail 1) $ in Thousands	Mar. 31, 2022 USD ($)
Revenue Performance Obligation Satisfied Over Time [Abstract]
Total Revenue	$ 29,543

Summary of Significant Accounting Policies - Schedule of Future Minimum Rental Income under Non-cancelable Operating Leases (Detail) $ in Thousands	Mar. 31, 2022 USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2022 (remainder of)	$ 9,828
2023	19,656
2024	19,656
2025	19,656
2026	19,656
Thereafter	72,474
Total	$ 160,926

Concentrations of Credit Risk - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Concentration Risk [Line Items]
Restricted cash	$ 3,351,000		$ 3,351,000		$ 3,350,000
Outstanding letters of credit to be collateralized by amounts on deposit	3,400,000		3,400,000
Allowance for doubtful accounts	$ 0		$ 0		$ 0
Sales Revenue, Net [Member] \| American Airlines Inc. [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	46.00%	45.00%	46.00%	46.00%
Sales Revenue, Net [Member] \| United [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	47.00%	53.00%	48.00%	52.00%

Intangible Assets - Information About Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Intangible Assets Net Excluding Goodwill [Abstract]
Customer relationship	$ 43,800	$ 43,800
Accumulated amortization	(37,519)	(37,008)
Net carrying value	$ 6,281	$ 6,792

Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Intangible Assets Net Excluding Goodwill [Abstract]
Amortization expense recognized	$ 0.3	$ 0.3	$ 0.5	$ 0.6
Amortization expense for remainder of 2022	0.5		0.5
Amortization expense for 2023	0.9		0.9
Amortization expense for 2024	0.8		0.8
Amortization expense for 2025	0.7		0.7
Amortization expense for 2026	0.6		0.6
Amortization expense, thereafter	$ 2.8		$ 2.8
Remaining weighted average term of intangible assets			13 years 6 months

Assets Held for Sale - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Impairment Charges [Member]
Long Lived Assets Held For Sale [Line Items]
Impairment losses	$ 39.5

Balance Sheet Information - Summary of Certain Significant Amounts Included in Condensed Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Expendable parts and supplies, net:
Expendable parts and supplies	$ 31,817	$ 29,297
Less: obsolescence and other	(5,562)	(4,830)
Expendable parts and supplies, net	26,255	24,467
Prepaid expenses and other current assets:
Prepaid aviation insurance	2,236	2,171
Lease incentives	1,792	1,445
Other	3,580	3,269
Prepaid expenses and other current assets	7,608	6,885
Property and equipment, net:
Property and equipment-gross	1,517,533	1,621,437
Less: accumulated depreciation	(453,184)	(469,546)
Property and equipment-net	1,064,349	1,151,891
Other assets:
Investments in equity securities	19,904	25,149
Lease incentives	12,904	10,957
Other	65	15
Other assets	32,873	36,121
Other accrued expenses:
Accrued property taxes	3,940	8,783
Accrued interest	2,546	2,565
Accrued vacation	5,190	5,936
Other	19,730	16,373
Other accrued expenses	31,406	33,657
Other noncurrent liabilities:
Warrant liabilities	25,225	21,964
Lease incentive obligations	6,503	6,358
Other	4,666	6,269
Other noncurrent liabilities	36,394	34,591
Aircraft and Other Flight Equipment [Member]
Property and equipment, net:
Property and equipment-gross	1,507,441	1,611,544
Other Machinery and Equipment [Member]
Property and equipment, net:
Property and equipment-gross	5,369	4,934
Leasehold Improvements [Member]
Property and equipment, net:
Property and equipment-gross	2,776	2,776
Vehicles [Member]
Property and equipment, net:
Property and equipment-gross	950	1,184
Building [Member]
Property and equipment, net:
Property and equipment-gross	699	699
Furniture and Fixtures [Member]
Property and equipment, net:
Property and equipment-gross	$ 298	$ 300

Balance Sheet Information - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Sep. 30, 2021	Jul. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Feb. 28, 2022	Feb. 28, 2021
Condensed Balance Sheet Statements Captions [Line Items]
Depreciation expense			$ 20.1	$ 20.4	$ 40.6	$ 40.6
Estimated initial equity warrant asset value								$ 16.4
Estimated initial warrant asset value							$ 3.2
Net losses on investments in equity securities			2.3		8.7
Aggregate carrying amount of investments in equity securities			19.9		19.9
Investments without readily determinable fair value			$ 9.0		$ 9.0
Heart Aerospace Incorporated [Member] \| Forward Purchase Contract [Member] \| Preferred Stock [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Purchase of preferred stock		$ 5.0
Initial investment in preferred stock measured at cost		$ 5.0
Class A [Member] \| Archer Aviation, Inc. [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Stock issued during period, Shares	500,000
Stock issued during period, Value	$ 5.0
Total grant date value, Additional warrant to purchase shares	$ 5.6

Fair Value Measurements - Carrying Value and Estimated Fair Value of Long-term Debt, Including Current Maturities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Long-term debt and finance leases, including current maturities, carrying value	$ 651,950	$ 670,335
Long-term debt and finance leases, including current maturities, fair value	$ 609,700	$ 676,800

Long-Term Debt, Finance Leases, and Other Borrowings - Schedule of Long-term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	$ 651,950	$ 670,335
Less unamortized debt issuance costs	(10,368)	(9,295)
Less notes payable warrants	(8,454)	(9,630)
Net long-term debt, including current maturities	633,128	651,410
Less current portion, net of unamortized debt issuance costs	(111,671)	(111,710)
Net long-term debt	521,457	539,700
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	15,630	22,930
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2027 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	80,244	86,551
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	141,690	152,100
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	114,883	122,762
Other Obligations Due to Financial Institution, Collateralized by the Underlying Equipment, Due 2023 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	3,448	4,581
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	36,290	45,559
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	21,875	30,625
Notes Payable to Financial Institution Due 2023 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	3,000	4,000
Notes Payable to U.S Treasury Due 2025 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	204,947	$ 201,227
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2027 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	$ 29,943

Long-Term Debt, Finance Leases, and Other Borrowings - Schedule of Long-term Debt (Parenthetical) (Detail)		1 Months Ended					6 Months Ended	12 Months Ended
	Sep. 25, 2019 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($) Airfleet	Jan. 31, 2019 USD ($)	Feb. 28, 2018 Engine	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2016 USD ($) Air-craft	Sep. 30, 2015 USD ($) Air-craft	Nov. 14, 2020 USD ($)	Nov. 13, 2020 USD ($)	Oct. 31, 2020 USD ($)	Oct. 30, 2020 USD ($)
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2027 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2027	2027
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2027 [Member] \| CRJ-900 [Member]
Debt Instrument [Line Items]
Number of aircraft financed \| Air-craft										7
Debt instrument, face amount										$ 170,200,000
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2028	2028
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] \| Ten E-175 Aircraft [Member]
Debt Instrument [Line Items]
Number of aircraft financed \| Air-craft									10
Debt instrument, face amount									$ 246,000,000.0
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] \| Ten E-175 Aircraft [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Long term debt interest rate percentage							4.75%
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] \| Ten E-175 Aircraft [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Long term debt interest rate percentage							6.25%
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2028	2028
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] \| Eight E-175 Aircraft [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, face amount									$ 195,300,000
Number of aircraft refinanced \| Air-craft									8
Other Obligations Due to Financial Institution, Collateralized by the Underlying Equipment, Due 2023 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2023	2023
Imputed interest						9.128%
Number of spare engines leased \| Engine						2
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2024	2024
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member] \| Flight Equipment [Member]
Debt Instrument [Line Items]
Debt instrument, face amount					$ 91,200,000
Long term debt interest rate description							monthly LIBOR plus 3.10%
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member] \| LIBOR [Member] \| Flight Equipment [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate					3.10%
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2023	2023
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member] \| CRJ-700 Aircraft [Member]
Debt Instrument [Line Items]
Number of aircraft financed \| Airfleet				10
Debt instrument, face amount				$ 70,000,000.0
Long term debt interest rate description							monthly LIBOR plus 5.00%
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member] \| CRJ-700 Aircraft [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate				5.00%
Notes Payable to Financial Institution Due 2023 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2023	2023
Notes Payable to Financial Institution Due 2023 [Member] \| Flight Equipment [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 8,000,000.0
Long term debt interest rate description							monthly LIBOR plus 5.00%
Notes Payable to Financial Institution Due 2023 [Member] \| LIBOR [Member] \| Flight Equipment [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate							5.00%
Notes Payable to U.S Treasury Due 2025 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2025	2025
Notes Payable to U.S Treasury Due 2025 [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Long term debt interest rate description							three-month LIBOR plus 3.50%
Long term debt, basis spread on variable rate							3.50%
Secured term loan facility, maximum borrowing capacity													$ 200,000,000.0
Secured term loan facility, amount borrowed														$ 43,000,000.0
Secured term loan facility, additional amount borrowed											$ 0	$ 152,000,000.0
Debt instrument, maturity date							Oct. 30, 2025
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2027 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year							2027	2027
Debt instrument, face amount		$ 30,800,000
Long term debt interest rate description							monthly LIBOR plus 4.25%
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2027 [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate		4.25%
Senior Notes Due Two Thousand Twenty Seven [Member] \| CRJ-900 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount										$ 154,700,000
Long term debt interest rate description							monthly LIBOR plus 2.71%
Senior Notes Due Two Thousand Twenty Seven [Member] \| CRJ-900 [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate										2.71%
Subordinated Notes Due Two Thousand Twenty Seven [Member] \| CRJ-900 [Member]
Debt Instrument [Line Items]
Imputed interest										6.25%
Debt discount										$ 8,100,000
Senior Notes Due 2008 [Member] \| Eight E-175 Aircraft [Member]
Debt Instrument [Line Items]
Long term debt interest rate description							three-month LIBOR plus a spread ranging from 2.20% to 2.32%
Senior Notes Due 2008 [Member] \| Eight E-175 Aircraft [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, face amount									$ 172,000,000.0
Senior Notes Due 2008 [Member] \| Eight E-175 Aircraft [Member] \| LIBOR [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate									2.20%
Senior Notes Due 2008 [Member] \| Eight E-175 Aircraft [Member] \| LIBOR [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate									2.32%
Subordinated Notes Due 2008 [Member] \| Eight E-175 Aircraft [Member]
Debt Instrument [Line Items]
Long term debt interest rate percentage							4.50%
Working Capital Draw Loan [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 35,000,000.0		$ 35,000,000.0
Long term debt interest rate description							one-month LIBOR plus 3.75%
Term loan, term	3 years		3 years
Debt instrument, expiration year and month	2022-09		2022-09
Working Capital Draw Loan [Member] \| LIBOR [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	3.75%		3.75%

Long-Term Debt, Finance Leases, and Other Borrowings - Schedule of Principal Maturities of Long-term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Long Term Debt By Maturity [Abstract]
2022 (remainder of)	$ 64,018
2023	94,670
2024	66,417
2025	61,734
2026	268,972
Thereafter	96,139
Long-term debt	$ 651,950	$ 670,335

Long-Term Debt, Finance Leases, and Other Borrowings - Additional Information (Detail)			1 Months Ended			6 Months Ended
	Oct. 30, 2020 USD ($) $ / shares shares	Sep. 25, 2019 USD ($)	Apr. 30, 2022	Dec. 31, 2021 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Apr. 09, 2020 $ / shares
Debt Instrument [Line Items]
Property and equipment-gross						$ 1,517,533,000	$ 1,621,437,000
Long-Term Debt						$ 633,128,000	$ 651,410,000
Warrants of common stock exercise price \| $ / shares									$ 3.98
Treasury Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Calculated collateral coverage ratio	1.6
Treasury Loan [Member] \| Maximum [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Minimum collateral coverage ratio covenant			1.5
Treasury Loan [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Additional collateral coverage ratio	1.6
Loan Agreement [Member]
Debt Instrument [Line Items]
Warrants to purchase shares of common stock \| shares	4,899,497
Warrants of common stock exercise price \| $ / shares	$ 3.98
Spare Engine Facility [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 30,800,000
Long term debt interest rate description						LIBOR plus 4.25%
Secured term loan facility, maximum borrowing capacity				$ 54,000,000.0
Debt instrument, maturity date				Dec. 31, 2027
Spare Engine Facility [Member] \| LIBOR [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate				4.25%
Equipment Notes [Member]
Debt Instrument [Line Items]
Long-Term Debt						$ 141,700,000
Working Capital Draw Loan [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 35,000,000.0			$ 35,000,000.0
Term loan, term		3 years			3 years
Debt instrument, expiration year and month		2022-09			2022-09
Long term debt interest rate description						one-month LIBOR plus 3.75%
Outstanding working capital draw loan						$ 15,600,000
Working Capital Draw Loan [Member] \| Revolving Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate		3.75%			3.75%
Secured Term Loan Facility [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Secured term loan facility, maximum borrowing capacity	$ 200,000,000.0
Debt instrument, maturity date						Oct. 30, 2025
Secured Term Loan Facility [Member] \| Loan Agreement [Member] \| Treasury Loan [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	3.50%
Secured term loan facility, amount borrowed								$ 195,000,000.0
Secured term loan facility, additional amount borrowed						$ 0
Debt instrument, maturity date	Oct. 30, 2025
Aircraft and Equipment [Member] \| Pledged as Collateral [Member]
Debt Instrument [Line Items]
Property and equipment-gross						$ 1,029,700,000

Earnings Per Share - Calculations of Net Income (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share And Equity [Abstract]
Net income (loss)	$ (42,783)	$ (14,274)	$ 5,689	$ 14,118	$ (57,057)	$ 19,807
Basic weighted average common shares outstanding	36,048,000		35,628,000		36,005,000	35,579,000
Add: Incremental shares for:
Dilutive effect of warrants			3,038			2,183
Dilutive effect of restricted stock			766			620
Diluted weighted average common shares outstanding	36,048,000		39,432,000		36,005,000	38,382,000
Net income (loss) per share attributable to common shareholders
Basic	$ (1.19)		$ 0.16		$ (1.58)	$ 0.56
Diluted	$ (1.19)		$ 0.14		$ (1.58)	$ 0.52

Earnings Per Share - Number of Weighted-Average Potentially Dilutive Shares Excluded from Calculation of Diluted Net Income (Loss) Per Share (Detail) - shares	3 Months Ended	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net income (loss) per share	902	1,906
Number of Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net income (loss) per share	818	1,671
Restricted Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net income (loss) per share	84	235

Common Stock - Additional Information (Detail) - $ / shares	Mar. 31, 2022	Sep. 30, 2021	Apr. 09, 2020
Stockholders Equity Note [Abstract]
Warrants of common stock exercise price			$ 3.98
Common stock, warrants issued	4,899,497	4,899,497
Common stock, warrants outstanding	4,899,497	4,899,497

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Income Taxes [Line Items]
Effective tax rate (ETR) from continuing operations	22.40%	24.90%	22.40%	25.30%
State net operating loss carryforwards					$ 1.2
Domestic Tax Authority [Member] \| 2027-2038 [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					541.3
State and Local Jurisdiction [Member] \| 2022-2041 [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					$ 235.7
Minimum [Member] \| Domestic Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year					2027
Minimum [Member] \| State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year					2022
Maximum [Member] \| Domestic Tax Authority [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year					2038
Maximum [Member] \| State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year					2041

Share-Based Compensation and Stock Repurchases - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested share-based compensation arrangements	$ 4,300				$ 4,300
Unrecognized compensation cost, period for recognition					1 year 7 months 6 days
Share-based compensation expense	700		$ 800		$ 1,400	$ 1,700
Repurchased shares, value	$ 60	$ 15	$ 157	$ 19
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchased shares, shares					15,696
Repurchased shares, value					$ 100
Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period					1 year
Restricted Stock Units [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period					3 years
Restricted Stock Units [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period					5 years

Share-Based Compensation and Stock Repurchases - Schedule of Restricted Share Activity (Detail) - Restricted Stock [Member]	6 Months Ended
	Mar. 31, 2022 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested, Beginning Balance \| shares	1,006,206
Number of Shares, Granted \| shares	187,993
Number of Shares, Vested \| shares	(130,094)
Number of Shares, Forfeited \| shares	(28,695)
Number of Shares, Unvested, Ending Balance \| shares	1,035,410
Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance \| $ / shares	$ 6.22
Weighted-Average Grant Date Fair Value, Granted \| $ / shares	4.72
Weighted-Average Grant Date Fair Value, Vested \| $ / shares	7.10
Weighted-Average Grant Date Fair Value, Forfeited \| $ / shares	10.08
Weighted-Average Grant Date Fair Value, Unvested, Ending Balance \| $ / shares	$ 5.73

Employee Stock Purchase Plan - Additional Information (Detail) - 2019 ESPP [Member] - shares	3 Months Ended	6 Months Ended	36 Months Ended
	Mar. 31, 2022	Mar. 31, 2022	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ordinary shares, discount rate		10.00%
Number of ordinary shares issued	53,567	53,567	247,761
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible employees contribution from their eligible compensation during each semi annual		1.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible employees contribution from their eligible compensation during each semi annual		15.00%
Number of ordinary shares issued		500,000

Leases - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
Leases - Additional Information (Detail) $ in Millions	Mar. 31, 2022 USD ($) Air-craft	Mar. 31, 2021 USD ($)	Mar. 31, 2022 USD ($) Air-craft	Mar. 31, 2021 USD ($)
Leases [Abstract]
Number of leased aircraft \| Air-craft	18		18
Aggregate rental expense under all operating aircraft, equipment and facility leases	$ 11.0	$ 11.3	$ 22.2	$ 22.7
Weighted average remaining lease term Operating leases	3 years 8 months 12 days		3 years 8 months 12 days
Weighted average discount rate Operating leases	4.40%		4.40%
Impairment of certain operating lease ROU assets	$ 0.4		$ 0.4

Leases - Components of Operating Lease Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Leases [Abstract]
Operating lease costs	$ 9,663	$ 9,697	$ 19,144	$ 19,405
Variable and short-term lease costs	1,346	1,646	3,081	3,335
Total lease costs	$ 11,009	$ 11,343	$ 22,225	$ 22,740

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended	6 Months Ended
	Dec. 31, 2022 Engine	Mar. 31, 2022 USD ($) Engine Lawsuit	Mar. 02, 2022 USD ($)	Jul. 31, 2021 USD ($)	Feb. 28, 2021 USD ($)
IPO [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Number of putative class action lawsuits \| Lawsuit		2
Agreement in principle to settle all claims \| $			$ 5,000,000.0
Superior Court of State of Arizona [Member] \| IPO [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Number of putative class action lawsuits \| Lawsuit		1
U.S. District Court of Arizona [Member] \| IPO [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Number of putative class action lawsuits \| Lawsuit		1
Forward Purchase Contract [Member] \| Heart Aerospace Incorporated [Member] \| Maximum [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Purchase commitment amount \| $				$ 1,200,000,000.0
CF34-8C5 or CF34-8E5 Engines [Member] \| Letter Agreement No. 13-3 [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Number of new spare engines to be acquired \| Engine		10
New spare engines delivery month and year description		We agreed to purchase and take delivery of ten (10) new CF34-8C5 or CF34-8E5 engines with delivery dates starting from July 1, 2021 through November 1, 2022. The total purchase commitment related to these ten (10) engines is approximately $52.2 million.
Purchase commitment amount \| $		$ 52,200,000
Number of additional spare engines to be acquired beyond 2022 \| Engine		10
Number of new spare engines purchased \| Engine		5
CF34-8C5 or CF34-8E5 Engines [Member] \| Forecast [Member] \| Letter Agreement No. 13-3 [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Number of new spare engines to be delivered \| Engine	5
eVTOL Aircraft [Member] \| Forward Purchase Contract [Member] \| Archer Aviation, Inc. [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Purchase commitment amount \| $					$ 200,000,000.0

Subsequent Events - Additional Information (Detail)	1 Months Ended
Subsequent Events - Additional Information (Detail)	Apr. 30, 2022
Maximum [Member] \| Treasury Loan [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Minimum collateral coverage ratio covenant	1.5