Mesa Air (MESA) 10-Q 11 Aug 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2023	Jul. 01, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
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		40,830,594

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Current assets:
Cash and cash equivalents	$ 48,349	$ 57,683
Restricted cash	3,146	3,342
Receivables, net ($493 and $85 from related party)	3,582	3,978
Expendable parts and supplies, net	28,731	26,715
Assets held for sale	90,954
Prepaid expenses and other current assets	6,364	6,616
Total current assets	181,126	98,334
Property and equipment, net	709,694	865,254
Intangible assets, net		3,842
Lease and equipment deposits	1,172	6,085
Operating lease right-of-use assets	11,416	43,090
Deferred heavy maintenance, net	8,753	9,707
Assets held for sale	21,000	73,000
Other assets	28,841	16,290
Total assets	962,002	1,115,602
Current liabilities:
Current portion of long-term debt and finance leases ($2,622 and $0 from related party)	124,341	97,218
Current portion of deferred revenue	6,398	385
Current maturities of operating leases	4,380	17,233
Accounts payable	51,916	59,386
Accrued compensation	8,358	11,255
Other accrued expenses	26,721	29,000
Total current liabilities	222,114	214,477
Noncurrent liabilities:
Long-term debt and finance leases, excluding current portion ($30,630 and $0 from related party)	441,941	502,517
Noncurrent operating lease liabilities	8,966	16,732
Deferred credits ($4,489 and $2,193 from related party)	4,489	3,082
Deferred income taxes	11,561	17,719
Deferred revenue, net of current portion	16,327	23,682
Other noncurrent liabilities	28,706	29,219
Total noncurrent liabilities	511,990	592,951
Total liabilities	734,104	807,428
Commitments and contingencies (Note 16)
Stockholders' equity:
Common stock of no par value and additional paid-in capital, 125,000,000 shares authorized; 40,830,594 (2023) and 36,376,897 (2022) shares issued and outstanding, 4,899,497 (2023) and 4,899,497 (2022) warrants issued and outstanding	270,673	259,177
Retained earnings/(Accumulated deficit)	(42,775)	48,997
Total stockholders' equity	227,898	308,174
Total liabilities and stockholders' equity	$ 962,002	$ 1,115,602

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Statement Of Financial Position [Abstract]
Recievables from related party	$ 493	$ 85
Current portion of long-term debt from related party	2,622	0
Non current portion of long-term debt from related party	30,630	0
Deferred credits from related party	$ 4,489	$ 2,193
Common stock, no par value	$ 0	$ 0
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	40,830,594	36,376,897
Common stock, shares outstanding	40,830,594	36,376,897
Common stock, warrants issued	4,899,497	4,899,497
Common stock, warrants outstanding	4,899,497	4,899,497

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating revenues:
Contract revenue	$ 114,691	$ 134,397	$ 383,699	$ 405,367
Operating expenses:
Flight operations	51,557	43,254	164,707	133,262
Maintenance	51,072	49,694	145,344	156,032
Aircraft rent	864	9,299	5,782	28,319
General and administrative	11,346	11,112	38,872	31,550
Depreciation and amortization	15,316	20,103	47,060	61,878
Asset impairment	30,489		50,951	39,475
(Gain) on sale of assets	(6,722)		(7,271)
Other operating expenses	999	722	2,358	3,379
Total operating expenses	154,921	134,184	447,803	453,895
Operating income/(loss)	(40,230)	213	(64,104)	(48,528)
Other income (expense), net:
Interest expense	(12,015)	(8,716)	(36,321)	(24,766)
Interest income	8	24	128	117
Gain/(Loss) on investments, net	2,859	(3,926)	3,275	(12,649)
Other income (expense), net	(946)	(73)	(540)	(203)
Total other expense, net	(10,094)	(12,691)	(33,458)	(37,501)
Loss before taxes	(50,324)	(12,478)	(97,562)	(86,029)
Income tax benefit	(2,764)	(2,493)	(5,791)	(18,987)
Net loss and comprehensive loss	$ (47,560)	$ (9,985)	$ (91,771)	$ (67,042)
Net loss per share attributable to common shareholders
Basic	$ (1.17)	$ (0.28)	$ (2.35)	$ (1.86)
Diluted	$ (1.17)	$ (0.28)	$ (2.35)	$ (1.86)
Weighted-average common shares outstanding
Basic	40,688	36,183	38,986	36,064
Diluted	40,688	36,183	38,986	36,064
Contract Revenue
Operating revenues:
Contract revenue	$ 94,356	$ 118,899	$ 326,588	$ 367,781
Pass Through and Other Revenue
Operating revenues:
Contract revenue	$ 20,335	$ 15,498	$ 57,111	$ 37,586

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Contract revenue, Related party	$ 88,415	$ 49,845	$ 200,184	$ 158,876

Condensed Consolidated Statem_3

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, 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
Payment of tax withholding for RSUs	(15)			(15)
Payment of tax withholding for RSUs, shares		(2,275)
Restricted shares issued, shares		7,500
Net 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
Net loss	(67,042)
Ending balance at Jun. 30, 2022	423,036			258,403	164,633
Ending balance, shares at Jun. 30, 2022		36,292,401	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
Payment of tax withholding for RSUs	(60)			(60)
Payment of tax withholding for RSUs, shares		(13,421)
Restricted shares issued, shares		122,594
Employee share purchases	239			239
Employee share purchases, shares		53,567
Net 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
Stock compensation expense	719			719
Payment of tax withholding for RSUs	(339)			(339)
Payment of tax withholding for RSUs, shares		(116,455)
Restricted shares issued	100			100
Restricted shares issued, shares		282,132
Net loss	(9,985)				(9,985)
Ending balance at Jun. 30, 2022	423,036			258,403	164,633
Ending balance, shares at Jun. 30, 2022		36,292,401	4,899,497
Beginning balance at Sep. 30, 2022	308,174			259,177	48,997
Beginning balance, shares at Sep. 30, 2022		36,376,897	4,899,497
Stock compensation expense	688			688
Payment of tax withholding for RSUs	(1)			(1)
Payment of tax withholding for RSUs, shares		(847)
Restricted shares issued, shares		2,500
Net loss	(9,090)				(9,090)
Ending balance at Dec. 31, 2022	299,771			259,864	39,907
Ending balance, shares at Dec. 31, 2022		36,378,550	4,899,497
Beginning balance at Sep. 30, 2022	308,174			259,177	48,997
Beginning balance, shares at Sep. 30, 2022		36,376,897	4,899,497
Net loss	(91,771)
Ending balance at Jun. 30, 2023	227,898			270,673	(42,775)
Ending balance, shares at Jun. 30, 2023		40,830,594	4,899,497
Beginning balance at Dec. 31, 2022	299,771			259,864	39,907
Beginning balance, shares at Dec. 31, 2022		36,378,550	4,899,497
Stock compensation expense	668			668
Payment of tax withholding for RSUs	(30)			(30)
Payment of tax withholding for RSUs, shares		(29,276)
Restricted shares issued, shares		175,661
United Stock Issuance	9,782			9,782
United Stock Issuance, Shares		4,042,061
Employee share purchases	148			148
Employee share purchases, shares		52,278
Net loss	(35,122)				(35,122)
Ending balance at Mar. 31, 2023	275,217			270,432	4,785
Ending balance, shares at Mar. 31, 2023		40,619,274	4,899,497
Stock compensation expense	556			556
Payment of tax withholding for RSUs	(315)			(315)
Payment of tax withholding for RSUs, shares		(163,920)
Restricted shares issued, shares		375,240
Net loss	(47,560)				(47,560)
Ending balance at Jun. 30, 2023	$ 227,898			$ 270,673	$ (42,775)
Ending balance, shares at Jun. 30, 2023		40,830,594	4,899,497

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net loss	$ (91,771)	$ (67,042)
Adjustments to reconcile net loss to net cash flows provided by (used in) operating activities:
Depreciation and amortization	47,060	61,878
Stock compensation expense	1,912	2,106
(Gain)/Loss on investments, net	(3,275)	12,649
Deferred income taxes	(6,157)	(19,137)
Amortization of deferred credits	1,407	(639)
Amortization of debt discount and issuance costs and accretion of interest into long-term debt	4,922	8,151
Asset impairment	50,951	39,475
Gain on sale of assets	(7,271)
Other	1,973	764
Changes in assets and liabilities:
Receivables	396	(883)
Expendable parts and supplies	(2,016)	(2,418)
Prepaid expenses and other operating assets and liabilities	125	(1,519)
Accounts payable	(6,349)	4,367
Deferred heavy maintenance, net	(1,382)	(4,536)
Deferred revenue	(1,342)	(11,780)
Accrued expenses and other liabilities	(5,689)	(10,949)
Operating lease right-of-use assets and liabilities	2,669	3,097
Net cash provided by (used in) operating activities	(13,837)	13,584
Cash flows from investing activities:
Capital expenditures	(31,619)	(33,230)
Investments in equity securities		(200)
Proceeds from sale of aircraft and engines	139,878
Refund (payment) of equipment and other deposits	740	(6,954)
Net cash provided by (used in) investing activities	108,999	(40,384)
Cash flows from financing activities:
Proceeds from long-term debt	39,000	35,311
Proceeds from issuance of common stock under ESPP	148	239
Principal payments on long-term debt and finance leases	(142,577)	(71,993)
Payments of debt and warrant issuance costs	(917)	(2,414)
Payment of tax withholding for RSUs	(346)	(414)
Net cash used in financing activities	(104,692)	(39,271)
Net change in cash, cash equivalents and restricted cash	(9,530)	(66,071)
Cash, cash equivalents and restricted cash at beginning of period	61,025	123,867
Cash, cash equivalents and restricted cash at end of period	51,495	57,796
Supplemental cash flow information
Cash paid for interest	28,801	14,695
Cash paid for income taxes , net	27	442
Operating lease payments in operating cash flows	8,203	31,069
Supplemental non-cash operating activities
Right-of-use assets obtained in exchange for lease liabilities	755	5,481
Supplemental non-cash financing activities
Finance lease obtained in exchange for lease liability	$ 65,094
Investments in warrants to purchase common stock		3,260
Accrued capital expenditures		$ 1,407

Insider Tagging Disclosure

Insider Tagging Disclosure	9 Months Ended
	Jun. 30, 2023
Insider Trading Arr [Lineitems]
Rule 10B51Arradoptedflag	false
Nonrule 10B51 Arradoptedflag	false
Rule10B51Arrtrmntdflag	false
Nonrule10B51Arrtrmntdflag	false

Organization and Operations

Organization and Operations	9 Months Ended
	Jun. 30, 2023
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, a regional air carrier providing scheduled passenger service to 89 cities in 40 states, the District of Columbia, the Bahamas, Canada, Cuba, and Mexico as well as cargo services out of Cincinnati/Northern Kentucky International Airport. As of June 30, 2023, Mesa operated a fleet of 80 regional aircraft with approximately 277 daily departures, four ( 4 ) 737 cargo aircraft and over 2,341 employees. Mesa’s flights were conducted 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. Mesa operates all of its flights as either United Express or DHL Express flights pursuant to the terms of the CPA entered into United Airlines, Inc. (“United”) and FSA with DHL Network Operations (USA), Inc. (“DHL”) (each, our “major partner”). Prior to the wind-down and termination of the Company's CPA with American Airlines, Inc. ("American") on April 3, 2023, Mesa also operated flights as American Eagle. All of the Company’s consolidated contract revenues for the three and nine months ended June 30, 2023 and June 30, 2022 were derived from operations associated with the American CPA prior to April 3, 2023, the United CPA, FSA, and leases of aircraft to a third party. The CPA between us and United involves a revenue-guarantee arrangement whereby United 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. United also pays certain expenses directly to suppliers, such as fuel, ground operations and landing fees. Under the terms of the CPA, United 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. Impact of Pilot Shortage and Transition of Operations to United During our three and nine months ended June 30, 2023 and fiscal year ended September 30, 2022, the severity of the pilot shortage, elevated pilot attrition, the transition of our operations with American to United, and increasing costs associated with pilot wages adversely impacted our financial results, cash flows, financial position, and other key financial ratios. One of the primary factors contributing to the pilot shortage and attrition is the demand for pilots at major carriers, which are hiring at an accelerated rate. These airlines now seek to increase their capacity to meet the growing demand for air travel as the global pandemic has moderated. A primary source of pilots for the major U.S. passenger and cargo carriers are the U.S. regional airlines. As a result of pilot shortage and attrition, we produced less block hours to generate revenues and incurred penalties for operational shortfalls under our CPAs. During the nine months ended June 30, 2023, these challenges resulted in a negative impact on the Company’s financial results highlighted by cash flows used in operations of $ 13.8 million and net loss of $ 91.8 million including a non-cash impairment charge of $ 51.0 million related to the Company designating 14 CRJ-900 aircraft as held for sale and our customer relationship intangible asset. These conditions and events raised financial concerns about our ability to continue to fund our operations and meet our debt obligations over the next twelve months. As of June 30, 2023, the Company is in compliance with all of its debt covenants. To address such concerns, management developed and implemented several material changes to our business designed to ensure the Company could continue to fund its operations and meet its debt obligations over the next twelve months. As previously disclosed plans in form 10-K for the fiscal year ended September 30, 2022, the following plans continue to be effective. • The Company and American agreed to terminate and complete a wind-down of the American CPA. The termination eliminated financial penalties incurred under the American CPA. • We entered into an agreement with a third party to sell eleven ( 11 ) of our CRJ-900 aircraft and one ( 1 ) CRJ-200 aircraft to raise capital and retire debt. Four ( 4 ) aircraft were sold during the quarter ended March 31, 2023, and we expect to complete the sale of the remaining seven ( 7 ) aircraft before 2023 fiscal year end. Sale from remaining seven ( 7 ) aircraft will generate approximately $ 21 million of gross proceeds. Furthermore, the Company implemented the following additional measures during the period. • Management is currently engaged in efforts to address the RASPRO aircraft repurchase obligation before it comes due. These efforts include, but are not limited to, obtaining equity financing, issuing debt, entering into other financing arrangements, securing a third party to purchase such aircraft, or restructuring the RASPRO aircraft lease facility. • On June 22, 2023, the Company closed on the sale of 20 spare engines to United. The approximate gross proceeds from this sale was $ 53.7 million, resulting in approximately $ 26.9 million of net proceeds after partial debt reduction of $ 7.8 million on the UMB engine loan, $ 7.9 million on the United Bridge Loan, and $ 11.2 million on the UST loan. This transaction completed the sale of the 30 engines to United under the Engine Sale Agreement entered into on December 27, 2022, as previously reported. The Company recorded a gain on the sale of the engines of $ 6.7 million for the 20 sold during the quarter, and $ 7.3 million for all 30 . • The Company entered into an agreement to sell seven ( 7 ) surplus CRJ-900 aircraft. The approximate gross proceeds from the sale of such aircraft is expected to be $ 71.8 million and to generate approximately $ 8.5 million of net proceeds after the retirement of debt. The sale of these aircraft will occur individually throughout the remainder of the fiscal year, with the final transaction expected to be completed in October 2023. • Management is in active discussion with United to provide additional liquidity through existing lines of credit and other means. • The Company has unencumbered parts that can be leveraged to provide additional liquidity. • In addition to already executed agreements to sell aircraft, the Company is actively seeking arrangements to sell other surplus assets including aircraft, engines, and spare parts to reduce debt and optimize operations. The Company believes the plans and initiatives outlined above have effectively alleviated the financial concerns above and will allow the Company to meet its cash obligations for the next twelve months following the issuance of its financial statements. While we intend to continue to implement and monitor our plans and initiatives, there is no guarantee that these actions will continue to be effective and achieve their desired objectives. As of June 30, 2023, the Company has $ 124.3 million of long-term debt due within the next twelve months. We plan to meet these obligations with our cash on hand, ongoing cashflows from our operations along with the liquidity we expect to achieve from disposition of surplus assets and other plans to improve cashflow from operations as outlined above. American Capacity Purchase Agreement For the first three days of the three months ended June 30, 2023, the Company operated 30 CRJ-900 aircraft under an Amended and Restated Capacity Purchase Agreement with American dated November 19, 2020 (as amended, the “American CPA”), after which the wind-down period of the American CPA was completed, and the American CPA was officially terminated. In exchange for providing passenger flight services, we received 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 also received incentives or incurred penalties based upon our operational performance, including controllable on-time departure (“CD0”) and controllable flight completion factor (“CCF”) percentages. American also reimbursed 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, were directly paid to suppliers by American. In addition, American also provided, 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 operated. In December 2022, we entered into Amendment No. 11 (the “American Amendment”) to the American CPA. The American Amendment provided for the termination and wind-down of the American CPA by April 3, 2023 (the “Wind-down Period”), at which time all Covered Aircraft (as defined in the American CPA) were removed from the American CPA. In March 2023, we began to transition aircraft operated under the American CPA to the United CPA. The American CPA was previously set to expire by its terms on December 31, 2025. Under the terms of the American Amendment, during the Wind-down Period (i) we continued to receive a fixed minimum monthly amount per aircraft covered by the American CPA, plus additional amounts based on the number of flights and block hours flown during each month, subject to adjustment based on the Company’s controllable completion rate and certain other factors, and (ii) American agreed not to exercise certain termination or withdrawal rights under the American CPA if we failed to meet certain operational performance targets for the three (3) consecutive month period ending January 31, 2023. We were in compliance with all of the terms of the American CPA during the Wind-down Period and no Material Breach (as defined in the American CPA) occurred. Pursuant to the American Amendment, as no material breaches occurred during the wind-down period, American agreed to waive Mesa’s failure to meet certain past operational performance targets and other requirements, which triggered termination and withdrawal rights for American pursuant to the terms of American CPA. All CCF targets were met during the Wind-down Period, and there were no penalties associated with that performance metric. The American Amendment provided for liquidated damages (the “Liquidated Damages Claim”) payable to American in the event of a Material Breach (as defined in the American CPA) of the American CPA or a repudiation by us of our obligations under the American CPA. No Material Breaches occurred during the wind-down period that would require the Company to pay any liquidated damages. The parties executed a written mutual release of all claims and acknowledgment that no Material Breaches have occurred under the American CPA (including, without limitation, any Liquidated Damages Claim). United Capacity Purchase Agreement Under the United CPA, we have the ability to fly up to 80 aircraft for United. The aircraft can be a mix of any number of E-175, E-175LL, or CRJ-900 aircraft so long as the number of aircraft operating at any given time does not exceed 80 . As of June 30, 2023, we operated 56 E-175 and 24 CRJ-900 aircraft under our Third Amended and Restated Capacity Purchase Agreement with United dated December 27, 2022, which amended and restated the Second Amended and Restated Capacity Purchase Agreement dated November 4, 2020 (as amended, the “United CPA” or the "Amended and Restated United CPA"). Under the United CPA, United owns 42 of our 60 E-175 aircraft and all of our 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 in 2032 and 2033 . 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. Our United CPA is subject to termination prior to its expiration, including under the following circumstances: • 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 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 ; and • If United elects to terminate our United CPA in its entirety or permanently remove aircraft from service, we are permitted to return any of the affected E-175 aircraft leased from United at no cost to us. 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 four ( 4) Boeing 737 aircraft which are leased to us from DHL and a third party to provide cargo air transportation services as of June 30, 2023. 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 expenses including fueling and airport fees are paid directly by DHL. Under our DHL FSA, DHL leases two (2) Boeing 737-400F aircraft and one (1) 737-800F 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. A third Boeing 737-400F aircraft is leased to us under an operating lease by a third party. The 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 (1) or more aircraft for a period of one year with 90 days’ advance written notice. Our DHL FSA is subject to the following termination rights prior to its expiration: • 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 (3) 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 control or ownership of the Company; and • DHL may terminate the agreement for a specific aircraft if it is subject to a total loss and the Company does 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 Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Jun. 30, 2023
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. 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, 2022 included in the Company's Annual Report on Form 10-K for the year ended September 30, 2022 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. Segment Reporting As of June 30, 2023 , our chief operating decision maker was the Chief Executive Officer. While we operate under a capacity purchase agreement 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 CPA and FSA. Under the CPA 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 CPA 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 nine months ended June 30, 2023, we recognized $ 1.8 million and $ 1.3 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 June 30, 2023 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 June 30, Total Deferred Revenue 2023 (remainder of) $ 522 2024 5,602 2025 7,347 2026 3,701 2027 3,358 Thereafter 2,195 Total $ 22,725 A portion of our compensation under our CPA with 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 CPA is accounted for as an operating lease and is reflected as contract revenue in the condensed consolidated statements of operations and comprehensive loss. We recognized $ 32.3 million and $ 38.7 million of lease revenue for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 111.4 million and $ 118.5 million during the nine months ended June 30, 2023 and June 30, 2022, respectively. We have not separately stated aircraft rental income in the condensed consolidated statements of operations and comprehensive loss because the use of the aircraft is not a separate activity from the total service provided under our CPA. Historically, the Company has lease agreements with GoJet Airlines LLC (“GoJet”) to lease 20 CRJ-700 aircraft. 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. The Company mitigated the residual asset risks through supplemental rent payments and by leasing aircraft and engine types that can be operated by the Company in the event of a default. Additionally, the leases have specified lease return condition requirements and we maintain inspection rights under the leases. Lease incentive obligations for reimbursements of certain aircraft maintenance costs are recognized as lease incentive assets and were amortized on a straight-line basis and recognized as a reduction to lease revenue over the lease term. During fiscal year 2022, the Company terminated its lease agreement with GoJet to lease 18 of the 20 CRJ-700 aircraft and classified the 18 aircraft as assets held for sale. All 18 aircraft were sold as of June 30, 2023. The remaining two (2) lease agreements are accounted for as finance leases. The following table summarizes future minimum rental payments under operating leases related to leased aircraft that had remaining non-cancelable lease terms as of June 30, 2023 (in thousands): Periods Ending June 30, Total Payments 2023 (remainder of) $ 546 2024 2,184 2025 2,184 2026 2,184 2027 2,184 Thereafter 8,008 Total $ 17,290 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, 18 of our aircraft are leased from third parties. 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. Contract Liabilities Contract liabilities consist of deferred credits for cost reimbursements from major partners related to aircraft modifications and pilot training associated with the capacity purchase agreement. 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 agreement. 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 June 30, 2023 and September 30, 2022 were $ 4.9 million and $ 3.9 million, respectively. We recognized $ 0.1 million and $ 0.2 million of the deferred credits within contract revenue during the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 1.6 million and $ 0.6 million during the nine months ended June 30, 2023 and June 30, 2022 , 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 $ 0.8 million and $ 0.5 million for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 2.3 million and $ 1.2 million for the nine months ended June 30, 2023 and June 30, 2022, respectively. As of June 30, 2023 and September 30, 2022, our deferred heavy maintenance balance, net of accumulated amortization, was $ 8.8 million and $ 9.7 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 $ 11.5 million and $ 8.1 million for the three months ended June 30, 2023 and June 30, 2022, respectively, of which $ 11.3 million and $ 6.0 million, respectively, was pass-through expense. Engine overhaul expense totaled $ 28.2 million and $ 18.2 million for the nine months ended June 30, 2023 and June 30, 2022, respectively, of which $ 27.9 million and $ 14.5 million, respectively was pass-through expense. Airframe C-check expense totaled $ 3.8 million and $ 5.0 million for the three months ended June 30, 2023 and June 30, 2022, respectively, of which $ 2.4 million and $ 1.3 million, respectively, was pass-through expense. Airframe C-check expense totaled $ 12.6 million and $ 18.8 million for the nine months ended June 30, 2023 and June 30, 2022, respectively, of which $ 8.6 million and $ 1.7 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 (1) 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 June 30, 2023 .

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Jun. 30, 2023
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	3. Recent Accounting Pronouncements 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. The U.S. Federal Reserve, in conjunction with the Alternative Reference Rates Committee, has determined that the U.S. dollar LIBOR will be replaced by the Secured Overnight Financing Rate (SOFR) after June 30, 2023. Optional expedients can be applied through December 31, 2024. Under the expedient, the Company will account for amendments to agreements as if the modification was not substantial. The new carrying amounts of debts will consist of the carrying amount of the original debt and any additional fees associated with the modified debt instrument. A new effective yield will be established based on the new carrying amount and revised cash flows. In June 2022, the FASB issued new guidance to clarify the fair value measurement guidance for equity securities subject to contractual restrictions that prohibit the sale of an equity security. Further, the guidance introduces new disclosure requirements for equity securities subject to contractual sale restrictions that are measured at fair value. The standard will be effective for annual reporting periods beginning after December 15, 2023, including interim reporting periods within those fiscal years. We are currently evaluating the impact that the new guidance will have on our consolidated financial statements.

Concentrations of Credit Risk

Concentrations of Credit Risk	9 Months Ended
	Jun. 30, 2023
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 June 30, 2023, we had $ 3.1 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, $ 3.3 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 nine months ended June 30, 2023 and June 30, 2022 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 June 30, 2023 and September 30, 2022 was derived from these agreements. American accounted for approximately 1 % and 46 % of our total revenue for the three months ended June 30, 2023 and June 30, 2022, respectively, and 31 % and 46 % of our total revenue for the nine months ended June 30, 2023 and June 30, 2022, respectively. United accounted for approximately 96 % and 47 % of our total revenue for the three months ended June 30, 2023 and June 30, 2022, respectively, and 65 % and 48 % of our total revenue for the nine months ended June 30, 2023 and June 30, 2022, respectively. The wind-down period of the American CPA ended on April 3, 2023, at which the American CPA was officially terminated. A termination of the 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 no t material as of June 30, 2023 or September 30, 2022 . 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

Intangible Assets	9 Months Ended
	Jun. 30, 2023
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	5. Intangible Assets Information about our intangible assets as of June 30, 2023 and September 30, 2022, is as follows (in thousands): June 30, September 30, 2023 2022 Customer relationship — $ 43,800 Accumulated amortization — ( 38,029 ) Impairment — ( 1,929 ) Net carrying value $ — $ 3,842 Total amortization expense recognized was $ 0 and $ 0.3 million for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 0.1 million and $ 0.8 million for the nine months ended June 30, 2023 and June 30, 2022 , respectively. The Company recognized an impairment loss of $ 3.7 million on the customer relationship related to the American CPA during the nine months ended June 30, 2023 , which was recorded in asset impairment on our condensed consolidated statements of operations and comprehensive loss. Accordingly, we expect to record amortization expense of zero for the remainder of 2023 and thereafter.

Assets Held for Sale

Assets Held for Sale	9 Months Ended
	Jun. 30, 2023
Discontinued Operations And Disposal Groups [Abstract]
Assets Held for Sale	6. Assets Held for Sale During 2022, our management committed to a formal plan to sell certain of our CRJ-900, CRJ-200, and CRJ-700 aircraft. 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. During the three months ended June 30, 2023 , the Company closed on the sale of 20 spare engines to United. The approximate gross proceeds from the sale was $ 53.7 million and generated approximately $ 26.9 million of net proceeds after partial debt reduction. This transaction completed the sale of the 30 engines to United under the Engine Sale Agreement entered into on December 27, 2022, as previously reported. The Company recorded a gain on the sale of the engines of $ 6.7 million for the 20 sold during the quarter, and $ 7.3 million for all 30 . During the three months ended June 30, 2023 , seven ( 7 ) CRJ-900 aircraft were designated as held for sale. The Company wrote down the value of the aircraft to the agreed upon sales price and recorded an impairment loss of $ 30.5 million. As of June 30, 2023 , the Company has 21 CRJ-900 aircraft and one ( 1 ) CRJ-200 aircraft that are classified as assets held for sale with a net book value of $ 112.0 million, which is reflected within assets held for sale on our condensed consolidated balance sheet.

Balance Sheet Information

Balance Sheet Information	9 Months Ended
	Jun. 30, 2023
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): June 30, September 30, 2023 2022 Expendable parts and supplies, net: Expendable parts and supplies $ 38,123 $ 31,913 Less: obsolescence and other ( 9,392 ) ( 5,198 ) $ 28,731 $ 26,715 Prepaid expenses and other current assets: Prepaid aviation insurance $ 3,176 $ 2,618 Prepaid vendors 143 1,310 Prepaid other insurance 1,290 1,268 Lease incentives 337 352 Prepaid fuel and other 1,418 1,068 $ 6,364 $ 6,616 Property and equipment, net: Aircraft and other flight equipment $ 1,041,056 $ 1,260,143 Other equipment 9,452 10,420 Total property and equipment 1,050,508 1,270,563 Less: accumulated depreciation ( 340,814 ) ( 405,309 ) $ 709,694 $ 865,254 Other assets: Investments in equity securities $ 18,187 $ 15,178 Lease incentives 990 1,097 Contract asset 9,149 — Other 515 15 $ 28,841 $ 16,290 Other accrued expenses: Accrued property taxes $ 4,682 $ 5,866 Accrued interest 5,247 2,882 Accrued vacation 6,832 4,746 Accrued lodging 4,181 3,795 Accrued maintenance 638 1,453 Accrued liability on government payroll program — 2,967 Accrued simulator costs 931 1,045 Accrued employee benefits 1,331 1,679 Accrued fleet operating expense 504 1,606 Short term lease incentive liability 97 97 Other 2,278 2,864 $ 26,721 $ 29,000 Other noncurrent liabilities: Warrant liabilities $ 25,225 $ 25,225 Lease incentive obligations 1,050 1,050 Long-term employee benefits 610 1,123 Other 1,821 1,821 $ 28,706 $ 29,219 Impairment of Long-lived Assets The Company monitors for any indicators of impairment of the long-lived fixed assets. When certain conditions or changes in the economic situation exist, the assets may be impaired and the carrying amount of the assets exceed their fair value. The assets are then tested for recoverability of carrying amount. The Company records 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 group assets at the capacity purchase agreement, flight services agreement, and fleet-type level (i.e., the lowest level for which there are identifiable cash flows). If impairment indicators exist with respect to any of the asset groups, we estimate future cash flows based on projections of capacity purchase or flight services agreement, block hours, maintenance events, labor costs and other relevant factors. During the fiscal year ended September 30, 2022, due to the impacts of the pilot shortage and the pilot wage increase, the Company assessed whether any indicators of impairment existed in any of our long-lived asset groups. The Company concluded there was impairment of its American asset group and recorded it as asset impairment in our condensed consolidated statements of operations and comprehensive loss. During the nine months ended June 30, 2023 , the Company qualitatively evaluated indictors of impairment and concluded that the remaining carrying value of the American intangible asset required impairment. The Company recognized a total impairment loss of $ 3.7 million related to the American intangible asset in the condensed consolidated statements of operations and comprehensive loss. Additionally, seven ( 7 ) CRJ-900 aircraft under the agreement with RASPRO Trust and seven ( 7 ) CRJ-900 aircraft under the agreement with Export Development Canada (EDC) reclassified to held for sale during the nine months ended June 30, 2023, were evaluated for impairment and determined that the carrying value of the assets exceeded their estimated fair value. The Company recognized an impairment loss of $ 30.5 million and $ 47.2 million during the three and nine months ended June 30, 2023, respectively, related to the held for sale aircraft. The Company determined that no other indicators of impairment were present during the quarter and no further steps were determined to be necessary. The Company’s assumptions about future conditions relevant to the assessment of potential impairment of its long-lived assets are subject to uncertainty, and the Company will continue to monitor these conditions in future periods as new information becomes available, and will update its analyses accordingly. Depreciation Expense on Property and Equipment: Depreciation of property and equipment totaled $ 15.3 million and $ 19.3 million for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 46.9 million and $ 59.9 million for the nine months ended June 30, 2023 and June 30, 2022, respectively. Other Assets In connection with a negotiated forward purchase contract for electrically-powered vertical takeoff and landing aircraft (“eVTOL aircraft”) executed in February 2021, we obtained equity warrant assets giving us the right to acquire a number shares of common stock in Archer Aviation, Inc. (“Archer”), which at the time of our initial investment was a private, venture-backed company. As the initial investment in Archer did not have a readily determinable fair value, we accounted for this investment using the measurement alternative under ASC 321, Investments – Equity Securities, and measured 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 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 reported in earnings, in accordance with ASC 321. The initial grant date values of the warrants, $ 16.4 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 eVTOL aircraft contemplated in the related aircraft purchase agreement. In connection with closing of the merger between Archer and the SPAC described above, in September 2021, 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. The initial value of the warrants was recognized as a vendor credit liability within other noncurrent liabilities, and 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. Because these investments have readily determinable fair values, gains and losses resulting from changes in fair value of the investments are reflected in earnings, in accordance with ASC 321. All of our vested warrants have been exercised into shares of Archer common stock. The fair values of the Company’s investments in Archer are 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 in 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 gain/(loss) on our investments in equity securities totaled $ 2.9 million and $ ( 3.9 ) million for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 3.3 million and $ ( 12.6 ) million for the nine months ended June 30, 2023 and June 30, 2022, respectively, and are reflected in gain/(loss) on investments, net in our condensed consolidated statements of operations and comprehensive loss. As of June 30, 2023 and September 30, 2022, the aggregate carrying amount of our investments in equity securities was $ 18.2 million and $ 15.2 million, respectively, and the carrying amount of our investments without readily determinable fair values was $ 8.8 million and $ 9.0 million, respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Jun. 30, 2023
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, which 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 June 30, 2023 and September 30, 2022. 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 and finance leases, including current maturities, were as follows (in millions): June 30, 2023 September 30, 2022 Carrying Fair Carrying Fair Value Value Value Value Long-term debt and finance leases, including current maturities (1) $ 577.5 $ 534.4 $ 615.3 $ 541.7 (1) Current and prior period long-term debts' carrying and fair values exclude net debt issuance costs.

Long-Term Debt, Finance Leases,

Long-Term Debt, Finance Leases, and Other Borrowings	9 Months Ended
	Jun. 30, 2023
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 June 30, 2023 and September 30, 2022, consisted of the following (in thousands): June 30, September 30, 2023 2022 Senior and subordinated notes payable to secured parties, due in monthly installments, interest based on LIBOR plus interest spread at 2.71 % through 2027 , collateralized by the underlying aircraft $ 67,206 $ 73,850 Notes payable to secured parties, due in semi-annual installments, interest based on LIBOR plus interest spread at 4.75 % to 6.25 % through 2028 , collateralized by the underlying aircraft 120,053 131,010 Notes payable to secured parties, due in quarterly installments, interest based on LIBOR plus interest at spread 2.20 % to 2.32 % for senior note & 4.50 % for subordinated note through 2028 , collateralized by the underlying aircraft 94,571 106,865 Revolving credit facility, quarterly interest based on SOFR plus interest spread at 4.50 % through 2028 , with incentives for up to $ 15 million based on achieving certain performance metrics 30,630 15,630 United Bridge Loan - due in quarterly installments based on SOFR plus interest spread at 4.50 % through 2024 2,622 - Other obligations due to financial institution, monthly and/or quarterly interest due from 2022 through 2031 , collateralized by the underlying equipment 72,657 18,038 Notes payable to financial institution, due in monthly installments, interest based on LIBOR plus interest spread at 3.10 % through 2024 , collateralized by the underlying equipment 1,869 26,758 Notes payable to financial institution, due in monthly installments, plus interest spread at 5.00 % through 2023 , secured by flight equipment — 2,000 Notes payable to financial institution, due in monthly installments, interest based on fixed interest of 7.50 %, through 2027 , collateralized by the underlying equipment 43,525 36,212 Notes payable to financial institution, quarterly interest based on LIBOR plus interest spread at 3.50 % through 2027 144,400 204,947 Gross long-term debt, including current maturities 577,533 615,310 Less unamortized debt issuance costs ( 5,745 ) ( 8,303 ) Less notes payable warrants ( 5,506 ) ( 7,272 ) Net long-term debt, including current maturities 566,282 599,735 Less current portion, net of unamortized debt issuance costs ( 124,341 ) ( 97,218 ) Net long-term debt $ 441,941 $ 502,517 Principal maturities of long-term debt as of June 30, 2023, and for each of the next five years are as follows (in thousands): Periods Ending June 30, Total Principal 2023 (remainder of) $ 23,893 2024 122,194 2025 70,222 2026 219,302 2027 89,200 Thereafter 52,721 $ 577,533 The carrying value of collateralized aircraft and equipment as of June 30, 2023 was approximately $ 729.8 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 June 30, 2023, we had $ 120.1 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. United Revolving Credit Facility On December 27, 2022, in connection with entering into the Amended and Restated United CPA, (i) United agreed to purchase and assume all of First Citizens’ rights and obligations as a lender under the Existing Facility pursuant to an Assignment and Assumption Agreement, (ii) United and CIT Bank agreed to amend the Existing Facility pursuant to an Amendment No. 1, dated December 27, 2022 (“Amendment No. 1”), and an Amendment No. 2, dated January 27, 2023 (“Amendment No. 2”; the Existing Facility as amended by Amendment No. 1 and Amendment No. 2, the "Amended Facility"), and (iii) Wilmington Trust, National Association agreed to assume all of CIT Bank’s rights and obligations as Administrative Agent pursuant to an Agency Resignation, Appointment and Assumption Agreement, dated as of January 27, 2023. Amendment No. 1, among other things, extends the Maturity Date from the earlier to occur of November 30, 2028, or the date of the termination of the Amended and Restated United CPA; provides for a revolving loan of $ 10.5 million plus fees and expenses, which is due January 31, 2024, subject to certain mandatory prepayment requirements; provides for Revolving Commitments equal to $ 30.7 million plus the original principal amount of the $ 10.5 million revolving loan; amortization of the obligations outstanding under the existing CIT Agreement commencing quarterly until March 31, 2025; and a covenant capping Restricted Payments (as defined in the Amended Facility) at $ 5.0 million per fiscal year, a consolidated interest and rental coverage ratio of 1.00 to 1.00 covenant, and a Liquidity (as defined in the Amended Facility) requirement of not less than $ 15.0 million at the close of any business day. Interest assessed under the Amended Facility is 3.50 % for Base Rate Loans and 4.50 % for Term SOFR Loans (as such terms are defined in the Amended Facility). Amendment No. 2, among other things, amends the definition of Controlled Account (as defined in the Amended Facility). Amounts borrowed under this Amended Facility are secured by a collateral pool consisting of a combination of expendable parts, rotable parts and engines and a pledge of the Company’s stock in certain aviation companies. United funded $ 25.5 million as of the closing date of Amendment No. 1, to be used for general corporate purposes. 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 . Commencing in June 2022, we initiated the payment of interest in lieu of increasing the principal amount of the loan. 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 (2) 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 sheets. In December 2022, we entered into an agreement with the U.S. Treasury to lower the minimum collateral coverage ratio ("CCR") covenant to 1.55 to 1.0 effective through the maturity date of the Treasury Loan and waive the CCR covenant requirement with respect to the release of liens on Collateral. We are in compliance with the terms of the Treasury Loan as of June 30, 2023. 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 $ 35.3 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. In December 2022, the agreement was amended for the borrowings under the loan agreement to bear a fixed interest rate of 7.5 %. 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, the LLC is consolidated in our financial statements and the borrowings are reflected as long-term debt in our condensed consolidated balance sheets. 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.

Loss Per Share

Loss Per Share	9 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Loss Per Share	10. Loss Per Share Calculations of net loss per common share were as follows (in thousands): Three Months Ended June 30, Nine Months Ended June 30, 2023 2022 2023 2022 Net loss $ ( 47,560 ) $ ( 9,985 ) $ ( 91,771 ) $ ( 67,042 ) Basic weighted average common shares outstanding 40,688 36,183 38,986 36,064 Diluted weighted average common shares outstanding 40,688 36,183 38,986 36,064 Net loss per common share attributable to Mesa Air Group: Basic $ ( 1.17 ) $ ( 0.28 ) $ ( 2.35 ) $ ( 1.86 ) Diluted $ ( 1.17 ) $ ( 0.28 ) $ ( 2.35 ) $ ( 1.86 ) 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 loss per share because the effect of including such potentially dilutive shares would have been anti-dilutive: Three Months Ended June 30, Nine Months Ended June 30, 2023 2022 2023 2022 Warrants — — — 1,011 Restricted stock — — — 142 — — — 1,153

Common Stock

Common Stock	9 Months Ended
	Jun. 30, 2023
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 June 30, 2023 , 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.

Income Taxes

Income Taxes	9 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes Our effective tax rate ("ETR") from continuing operations was 5.5 % and 5.9 % for the three and nine months ended June 30, 2023, respectively, and 19.9 % and 22.1 % for the three and nine months ended June 30, 2022, respectively. The Company’s ETR during the three and nine months ended June 30, 2023 decreased from the prior year tax rate, primarily as a result of certain tax differences, state taxes, and changes in the valuation allowance against federal and state net operating losses. We maintain a valuation allowance on a portion of our federal and 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, 2022 , the Company had aggregate federal and state net operating loss carryforwards of approximately $ 591.4 million and $ 247.0 million, respectively, which expire in fiscal years 2027 - 2038 and 2023 - 2043 , respectively. Approximately $ 5.2 million of state net operating loss carryforwards are expected to expire in the current fiscal year.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Jun. 30, 2023
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	13. Share-Based Compensation 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 three ( 3 ) to five ( 5 ) years for employees and one ( 1 ) 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 nine months ended June 30, 2023 is summarized as follows: Weighted- Average Number Grant Date of Shares Fair Value Restricted shares unvested at September 30, 2022 1,172,493 $ 4.43 Granted 483,723 $ 2.43 Vested ( 553,755 ) $ 4.61 Forfeited ( 220,533 ) $ 3.39 Restricted shares unvested at June 30, 2023 881,928 $ 3.65 As of June 30, 2023, there was $ 2.7 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 1.4 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 June 30, 2023 and June 30, 2022 was $ 0.6 million and $ 0.7 million, respectively, and for the nine months ended June 30, 2023 and June 30, 2022 was $ 1.9 million and $ 2.1 million, respectively. Shares for Restricted Stock Units Tax Withholding The amounts remitted for employee withholding taxes during the three months ended June 30, 2023 and June 30, 2022 were $ 0.3 million and $ 0.4 million, respectively, for which the Company withheld 163,920 and 132,151 shares of our common stock, respectively, that were underlying the RSUs that vested.

Employee Stock Purchase Plan

Employee Stock Purchase Plan	9 Months Ended
	Jun. 30, 2023
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 ( "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 June 30, 2023, eligible employees purchased and we issued an aggregate of 356,415 Mesa Air Group, Inc. ordinary shares under the 2019 ESPP, 52,278 of which were purchased and issued during the nine months ended June 30, 2023 .

Leases

Leases	9 Months Ended
	Jun. 30, 2023
Leases [Abstract]
Leases	15. Leases As of June 30, 2023, we leased 18 aircraft, airport facilities, office space, and other property and equipment under non-cancelable operating and finance leases. The leases generally require us to pay all taxes, maintenance, insurance, and other operating expenses. Operating leased expense is recognized as a rental expense on a straight-line basis over the lease term, net of lessor rebates and other incentives. Finance lease is capitalized and depreciated over the useful life of the asset. Aggregate rental expense under all aircraft, equipment and facility leases totaled approximately $ 3.6 million and $ 10.8 million for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 14.3 million and $ 33.1 million for the nine months ended June 30, 2023 and June 30, 2022, respectively. The components of our lease costs were as follows (in thousands): Three Months Ended June 30, Nine Months Ended June 30, 2023 2022 2023 2022 Operating lease costs $ 1,283 $ 9,534 $ 7,259 $ 28,678 Variable and short-term lease costs 998 1,311 $ 3,121 $ 4,392 Interest expense on finance lease liabilities 230 — $ 734 — Amortization expense of finance lease assets 1,046 — 3,138 — Total lease costs $ 3,557 $ 10,845 $ 14,252 $ 33,070 As of June 30, 2023, our operating leases have a remaining weighted average lease term of 6.2 years and our operating lease liabilities were measured using a weighted average discount rate of 5.3 % . RASPRO Lease Facility Historically, Mesa Airlines, as lessee, entered into the RASPRO Lease Facility, with RASPRO as lessor, for 15 of our CRJ-900 aircraft classified as operating leases. The obligations under the RASPRO Lease Facility are guaranteed by us, and basic rent is paid quarterly on each aircraft. During December 2022, the Company entered into an agreement with RASPRO Trust, reducing the buyout pricing on all 15 aircraft at lease termination by a total of $ 25 million. Under the terms of the new agreement, the Company reclassified these leases as finance leases.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jun. 30, 2023
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. Commitments and Contingencies Litigation We are subject to certain legal actions which we consider routine to our business activities. As of June 30, 2023, our management believed the ultimate outcomes of other routine legal matters are not likely to have a material adverse effect on our financial position, liquidity or results of operations. 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

Subsequent Events	9 Months Ended
	Jun. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	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. 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, 2022 included in the Company's Annual Report on Form 10-K for the year ended September 30, 2022 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.
Segment Reporting	Segment Reporting As of June 30, 2023 , our chief operating decision maker was the Chief Executive Officer. While we operate under a capacity purchase agreement 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	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	Contract Revenue and Pass-through and Other Revenue We recognize contract revenue when the service is provided under our CPA and FSA. Under the CPA 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 CPA 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 nine months ended June 30, 2023, we recognized $ 1.8 million and $ 1.3 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 June 30, 2023 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 June 30, Total Deferred Revenue 2023 (remainder of) $ 522 2024 5,602 2025 7,347 2026 3,701 2027 3,358 Thereafter 2,195 Total $ 22,725 A portion of our compensation under our CPA with 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 CPA is accounted for as an operating lease and is reflected as contract revenue in the condensed consolidated statements of operations and comprehensive loss. We recognized $ 32.3 million and $ 38.7 million of lease revenue for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 111.4 million and $ 118.5 million during the nine months ended June 30, 2023 and June 30, 2022, respectively. We have not separately stated aircraft rental income in the condensed consolidated statements of operations and comprehensive loss because the use of the aircraft is not a separate activity from the total service provided under our CPA. Historically, the Company has lease agreements with GoJet Airlines LLC (“GoJet”) to lease 20 CRJ-700 aircraft. 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. The Company mitigated the residual asset risks through supplemental rent payments and by leasing aircraft and engine types that can be operated by the Company in the event of a default. Additionally, the leases have specified lease return condition requirements and we maintain inspection rights under the leases. Lease incentive obligations for reimbursements of certain aircraft maintenance costs are recognized as lease incentive assets and were amortized on a straight-line basis and recognized as a reduction to lease revenue over the lease term. During fiscal year 2022, the Company terminated its lease agreement with GoJet to lease 18 of the 20 CRJ-700 aircraft and classified the 18 aircraft as assets held for sale. All 18 aircraft were sold as of June 30, 2023. The remaining two (2) lease agreements are accounted for as finance leases. The following table summarizes future minimum rental payments under operating leases related to leased aircraft that had remaining non-cancelable lease terms as of June 30, 2023 (in thousands): Periods Ending June 30, Total Payments 2023 (remainder of) $ 546 2024 2,184 2025 2,184 2026 2,184 2027 2,184 Thereafter 8,008 Total $ 17,290
Leases	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, 18 of our aircraft are leased from third parties. 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.
Contract Liabilities	Contract Liabilities Contract liabilities consist of deferred credits for cost reimbursements from major partners related to aircraft modifications and pilot training associated with the capacity purchase agreement. 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 agreement. 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 June 30, 2023 and September 30, 2022 were $ 4.9 million and $ 3.9 million, respectively. We recognized $ 0.1 million and $ 0.2 million of the deferred credits within contract revenue during the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 1.6 million and $ 0.6 million during the nine months ended June 30, 2023 and June 30, 2022 , respectively.
Maintenance Expense	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 $ 0.8 million and $ 0.5 million for the three months ended June 30, 2023 and June 30, 2022, respectively, and $ 2.3 million and $ 1.2 million for the nine months ended June 30, 2023 and June 30, 2022, respectively. As of June 30, 2023 and September 30, 2022, our deferred heavy maintenance balance, net of accumulated amortization, was $ 8.8 million and $ 9.7 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 $ 11.5 million and $ 8.1 million for the three months ended June 30, 2023 and June 30, 2022, respectively, of which $ 11.3 million and $ 6.0 million, respectively, was pass-through expense. Engine overhaul expense totaled $ 28.2 million and $ 18.2 million for the nine months ended June 30, 2023 and June 30, 2022, respectively, of which $ 27.9 million and $ 14.5 million, respectively was pass-through expense. Airframe C-check expense totaled $ 3.8 million and $ 5.0 million for the three months ended June 30, 2023 and June 30, 2022, respectively, of which $ 2.4 million and $ 1.3 million, respectively, was pass-through expense. Airframe C-check expense totaled $ 12.6 million and $ 18.8 million for the nine months ended June 30, 2023 and June 30, 2022, respectively, of which $ 8.6 million and $ 1.7 million, respectively, was pass-through expense.
Assets Held for Sale	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 (1) 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 June 30, 2023 .

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Schedule of Deffered Revenue Remaining Performance Obligations	Periods Ending June 30, Total Deferred Revenue 2023 (remainder of) $ 522 2024 5,602 2025 7,347 2026 3,701 2027 3,358 Thereafter 2,195 Total $ 22,725
Schedule of Future Minimum Rental Payments under Non-cancelable Operating Leases	Periods Ending June 30, Total Payments 2023 (remainder of) $ 546 2024 2,184 2025 2,184 2026 2,184 2027 2,184 Thereafter 8,008 Total $ 17,290

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Jun. 30, 2023
Goodwill And Intangible Assets Disclosure [Abstract]
Information About Intangible Assets	Information about our intangible assets as of June 30, 2023 and September 30, 2022, is as follows (in thousands): June 30, September 30, 2023 2022 Customer relationship — $ 43,800 Accumulated amortization — ( 38,029 ) Impairment — ( 1,929 ) Net carrying value $ — $ 3,842

Balance Sheet Information (Tabl

Balance Sheet Information (Tables)	9 Months Ended
	Jun. 30, 2023
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): June 30, September 30, 2023 2022 Expendable parts and supplies, net: Expendable parts and supplies $ 38,123 $ 31,913 Less: obsolescence and other ( 9,392 ) ( 5,198 ) $ 28,731 $ 26,715 Prepaid expenses and other current assets: Prepaid aviation insurance $ 3,176 $ 2,618 Prepaid vendors 143 1,310 Prepaid other insurance 1,290 1,268 Lease incentives 337 352 Prepaid fuel and other 1,418 1,068 $ 6,364 $ 6,616 Property and equipment, net: Aircraft and other flight equipment $ 1,041,056 $ 1,260,143 Other equipment 9,452 10,420 Total property and equipment 1,050,508 1,270,563 Less: accumulated depreciation ( 340,814 ) ( 405,309 ) $ 709,694 $ 865,254 Other assets: Investments in equity securities $ 18,187 $ 15,178 Lease incentives 990 1,097 Contract asset 9,149 — Other 515 15 $ 28,841 $ 16,290 Other accrued expenses: Accrued property taxes $ 4,682 $ 5,866 Accrued interest 5,247 2,882 Accrued vacation 6,832 4,746 Accrued lodging 4,181 3,795 Accrued maintenance 638 1,453 Accrued liability on government payroll program — 2,967 Accrued simulator costs 931 1,045 Accrued employee benefits 1,331 1,679 Accrued fleet operating expense 504 1,606 Short term lease incentive liability 97 97 Other 2,278 2,864 $ 26,721 $ 29,000 Other noncurrent liabilities: Warrant liabilities $ 25,225 $ 25,225 Lease incentive obligations 1,050 1,050 Long-term employee benefits 610 1,123 Other 1,821 1,821 $ 28,706 $ 29,219

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Carrying Value and Estimated Fair Value of Long-term Debt and Finance Leases, Including Current Maturities	The carrying value and estimated fair value of our total long-term debt and finance leases, including current maturities, were as follows (in millions): June 30, 2023 September 30, 2022 Carrying Fair Carrying Fair Value Value Value Value Long-term debt and finance leases, including current maturities (1) $ 577.5 $ 534.4 $ 615.3 $ 541.7 (1) Current and prior period long-term debts' carrying and fair values exclude net debt issuance costs.

Long-Term Debt, Finance Lease_2

Long-Term Debt, Finance Leases, and Other Borrowings (Tables)	9 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt as of June 30, 2023 and September 30, 2022, consisted of the following (in thousands): June 30, September 30, 2023 2022 Senior and subordinated notes payable to secured parties, due in monthly installments, interest based on LIBOR plus interest spread at 2.71 % through 2027 , collateralized by the underlying aircraft $ 67,206 $ 73,850 Notes payable to secured parties, due in semi-annual installments, interest based on LIBOR plus interest spread at 4.75 % to 6.25 % through 2028 , collateralized by the underlying aircraft 120,053 131,010 Notes payable to secured parties, due in quarterly installments, interest based on LIBOR plus interest at spread 2.20 % to 2.32 % for senior note & 4.50 % for subordinated note through 2028 , collateralized by the underlying aircraft 94,571 106,865 Revolving credit facility, quarterly interest based on SOFR plus interest spread at 4.50 % through 2028 , with incentives for up to $ 15 million based on achieving certain performance metrics 30,630 15,630 United Bridge Loan - due in quarterly installments based on SOFR plus interest spread at 4.50 % through 2024 2,622 - Other obligations due to financial institution, monthly and/or quarterly interest due from 2022 through 2031 , collateralized by the underlying equipment 72,657 18,038 Notes payable to financial institution, due in monthly installments, interest based on LIBOR plus interest spread at 3.10 % through 2024 , collateralized by the underlying equipment 1,869 26,758 Notes payable to financial institution, due in monthly installments, plus interest spread at 5.00 % through 2023 , secured by flight equipment — 2,000 Notes payable to financial institution, due in monthly installments, interest based on fixed interest of 7.50 %, through 2027 , collateralized by the underlying equipment 43,525 36,212 Notes payable to financial institution, quarterly interest based on LIBOR plus interest spread at 3.50 % through 2027 144,400 204,947 Gross long-term debt, including current maturities 577,533 615,310 Less unamortized debt issuance costs ( 5,745 ) ( 8,303 ) Less notes payable warrants ( 5,506 ) ( 7,272 ) Net long-term debt, including current maturities 566,282 599,735 Less current portion, net of unamortized debt issuance costs ( 124,341 ) ( 97,218 ) Net long-term debt $ 441,941 $ 502,517
Schedule of Principal Maturities of Long-term Debt	Principal maturities of long-term debt as of June 30, 2023, and for each of the next five years are as follows (in thousands): Periods Ending June 30, Total Principal 2023 (remainder of) $ 23,893 2024 122,194 2025 70,222 2026 219,302 2027 89,200 Thereafter 52,721 $ 577,533

Loss Per Share (Tables)

Loss Per Share (Tables)	9 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Calculations of Net Loss Per Common Share	Calculations of net loss per common share were as follows (in thousands): Three Months Ended June 30, Nine Months Ended June 30, 2023 2022 2023 2022 Net loss $ ( 47,560 ) $ ( 9,985 ) $ ( 91,771 ) $ ( 67,042 ) Basic weighted average common shares outstanding 40,688 36,183 38,986 36,064 Diluted weighted average common shares outstanding 40,688 36,183 38,986 36,064 Net loss per common share attributable to Mesa Air Group: Basic $ ( 1.17 ) $ ( 0.28 ) $ ( 2.35 ) $ ( 1.86 ) Diluted $ ( 1.17 ) $ ( 0.28 ) $ ( 2.35 ) $ ( 1.86 )
Number of Weighted-Average Potentially Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share	The following number of weighted-average potentially dilutive shares were excluded from the calculation of diluted net loss per share because the effect of including such potentially dilutive shares would have been anti-dilutive: Three Months Ended June 30, Nine Months Ended June 30, 2023 2022 2023 2022 Warrants — — — 1,011 Restricted stock — — — 142 — — — 1,153

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Jun. 30, 2023
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Restricted Share Activity	The restricted share activity for the nine months ended June 30, 2023 is summarized as follows: Weighted- Average Number Grant Date of Shares Fair Value Restricted shares unvested at September 30, 2022 1,172,493 $ 4.43 Granted 483,723 $ 2.43 Vested ( 553,755 ) $ 4.61 Forfeited ( 220,533 ) $ 3.39 Restricted shares unvested at June 30, 2023 881,928 $ 3.65

Leases (Tables)

Leases (Tables)	9 Months Ended
	Jun. 30, 2023
Leases [Abstract]
Components of Lease Costs	The components of our lease costs were as follows (in thousands): Three Months Ended June 30, Nine Months Ended June 30, 2023 2022 2023 2022 Operating lease costs $ 1,283 $ 9,534 $ 7,259 $ 28,678 Variable and short-term lease costs 998 1,311 $ 3,121 $ 4,392 Interest expense on finance lease liabilities 230 — $ 734 — Amortization expense of finance lease assets 1,046 — 3,138 — Total lease costs $ 3,557 $ 10,845 $ 14,252 $ 33,070

Organization and Operations - A

Organization and Operations - Additional Information (Detail) $ / shares in Units, $ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2023 USD ($) AirCraft

Jun. 22, 2023 USD ($) Engine

Apr. 03, 2023 AirCraft

Dec. 20, 2019 AirCraft

Jun. 30, 2023 USD ($) DailyDeparture Engine State AirCraft $ / shares shares

Mar. 31, 2023 USD ($) AirCraft

Dec. 31, 2022 USD ($)

Jun. 30, 2022 USD ($)

Mar. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Jun. 30, 2023 USD ($) DailyDeparture AirCraft Engine City Employee State $ / shares shares

Jun. 30, 2022 USD ($)

Sep. 30, 2022 USD ($) $ / shares shares

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of states in which entity operates | State

40

40

Number of aircrafts operated

80

Number of cities in which entity operates | City

89

Number of daily departures | DailyDeparture

277

277

Number of employees | Employee

2,341

Net cash provided by operating activities | $

$ (13,837)

$ 13,584

Net income (loss) | $

$ (47,560)

$ (35,122)

$ (9,090)

$ (9,985)

$ (42,783)

$ (14,274)

(91,771)

$ (67,042)

Long-term debt | $

124,300

124,300

Deferred income taxes | $

$ 11,561

$ 11,561

$ 17,719

Number of leased aircraft

18

18

United capacity purchase agreement termination notice period

30 days

Common stock, no par value | $ / shares

$ 0

$ 0

$ 0

Common stock, shares issued | shares

40,830,594

40,830,594

36,376,897

Impact of Pilot Shortage and Transition of Operations to United [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Net cash provided by operating activities | $

$ 13,800

Net income (loss) | $

91,800

Non-cash impairment charge | $

$ 51,000

United [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircraft sold | Engine

30

Number of spare engines to be sold | Engine

20

20

Gross proceeds from sale of asset | $

$ 53,700

$ 53,700

Number of engine sold | Engine

20

30

Gain on the sale of engines | $

$ 6,700

$ 7,300

Proceeds from sale of asset | $

$ 26,900

$ 26,900

United [Member] | Engine Sale Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of engine sold | Engine

30

30

United Capacity Purchase Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

80

B-737 Aircraft [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

4

CRJ-900 Aircraft [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts listed for sale

11

Number of surplus aircraft to be sold

7

Proceeds from sale of property | $

$ 8,500

Number of aircraft sold

4

Number of aircraft classified as assets held for sale

14

Gross proceeds from sale of asset | $

$ 71,800

CRJ-900 Aircraft [Member] | Forecast [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircraft sold

7

Gross proceeds from sale of asset | $

$ 21,000

CRJ-900 Aircraft [Member] | American Capacity Purchase Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

30

CRJ-900 Aircraft [Member] | United Capacity Purchase Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

24

CRJ-200 Aircraft [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts listed for sale

1

E-175 Aircraft [Member] | United Capacity Purchase Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

56

E-175 Aircraft [Member] | United Capacity Purchase Agreement [Member] | United [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

42

Number of aircrafts owned

18

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

E-175 Aircraft [Member] | United Capacity Purchase Agreement [Member] | United [Member] | Minimum [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Lease expiration year

2024

E-175 Aircraft [Member] | United Capacity Purchase Agreement [Member] | United [Member] | Maximum [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Lease expiration year

2028

E175LL Aircraft [Member] | United Capacity Purchase Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Air crafts expiring month and year description

in 2032 and 2033

Boeing 737400F [Member] | DHL Flight Services Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircrafts operated

4

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 (1) or more aircraft for a period of one year with 90 days’ advance written notice.

Boeing 737-800F [Member] | DHL Flight Services Agreement [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Number of aircraft leased

1

UMB Engine Loan [Member] | United [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Debt reduction amount | $

$ 7,800

United Bridge Loan [Member] | United [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Debt reduction amount | $

7,900

UST Loan [Member] | United [Member]

Organization Consolidation And Presentation Of Financial Statements [Line Items]

Debt reduction amount | $

$ 11,200

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2023 USD ($) AirCraft	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) AirCraft	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($) AirCraft
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue		$ 1.8		$ 1.3
Lease revenue		$ 32.3	$ 38.7	$ 111.4	$ 118.5
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]		Revenue From Contract With Customer Excluding Assessed Tax	Revenue From Contract With Customer Excluding Assessed Tax
Number of air craft leased from third parties | AirCraft				18
Current and non-current deferred credit contract liability balances	$ 4.9	$ 4.9		$ 4.9		$ 3.9
Recognized deferred credits within contract revenue		0.1	$ 0.2	1.6	0.6
Amortization of heavy maintenance and major overhaul costs charged to depreciation and amortization expense		0.8	0.5	2.3	1.2
Deferred heavy maintenance balance, net of accumulated amortization	$ 8.8	8.8		8.8		$ 9.7
Engine overhaul expense		11.5	8.1	28.2	18.2
Engine overhaul pass-through expense		11.3	6	27.9	14.5
Airframe check expense		3.8	5	12.6	18.8
Airframe check pass-through expense		$ 2.4	$ 1.3	$ 8.6	$ 1.7
CRJ 700 [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of aircraft to be leased | AirCraft				20		20
Operating lease, term of contract	9 years	9 years		9 years
CRJ 700 [Member] | GoJet Agreements [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of aircraft classified as assets held for sale | AirCraft						18
Number of aircraft sold | AirCraft	18

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Deferred Revenue Remaining Performance Obligations (Detail) $ in Thousands	Jun. 30, 2023 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Deferred Revenue	$ 22,725
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-04-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Deferred Revenue	$ 522
Deferred 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 Deferred Revenue	$ 5,602
Deferred 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 Deferred Revenue	$ 7,347
Deferred 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 Deferred Revenue	$ 3,701
Deferred 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 Deferred Revenue	$ 3,358
Deferred Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2027-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Deferred Revenue	$ 2,195
Deferred Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Deferred Revenue Remaining Performance Obligations (Detail 1) $ in Thousands	Jun. 30, 2023 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total Deferred Revenue	$ 22,725

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Future Minimum Rental Payments under Non-cancelable Operating Leases (Detail) $ in Thousands	Jun. 30, 2023 USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2023 (remainder of)	$ 546
2024	2,184
2025	2,184
2026	2,184
2027	2,184
Thereafter	8,008
Total	$ 17,290

Concentrations of Credit Risk -

Concentrations of Credit Risk - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Concentration Risk [Line Items]
Restricted cash	$ 3,146,000		$ 3,146,000		$ 3,342,000
Outstanding letters of credit to be collateralized by amounts on deposit	3,300,000		3,300,000
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	1%	46%	31%	46%
Sales Revenue, Net [Member] | United [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	96%	47%	65%	48%

Intangible Assets - Information

Intangible Assets - Information About Intangible Assets (Detail) $ in Thousands	Sep. 30, 2022 USD ($)
Intangible Assets Net Excluding Goodwill [Abstract]
Customer relationship	$ 43,800
Accumulated amortization	(38,029)
Impairment	(1,929)
Net carrying value	$ 3,842

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Finite-Lived Intangible Assets [Line Items]
Impairment loss on intangible assets	$ 30,489,000		$ 50,951,000	$ 39,475,000
Amortization expense recognized	0	$ 300,000	100,000	$ 800,000
Amortization expense for remainder of fiscal year and thereafter	$ 0		0
Customer Relationships [Member] | American Capacity Purchase Agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment loss on intangible assets			$ 3,700,000

Assets Held for Sale - Addition

Assets Held for Sale - Additional Information (Detail) $ in Thousands		3 Months Ended	9 Months Ended
	Jun. 22, 2023 USD ($) Engine	Jun. 30, 2023 USD ($) Engine	Jun. 30, 2023 USD ($) AirCraft Engine	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)
Long Lived Assets Held For Sale [Line Items]
Asset impairment			$ 50,951	$ 39,475
Assets held for sale		$ 21,000	21,000		$ 73,000
Proceeds from sale of aircraft and engines			$ 139,878
CRJ-900 [Member]
Long Lived Assets Held For Sale [Line Items]
Asset impairment		$ 30,500
Number of aircraft held for sale		7	21
CRJ-200 Aircraft [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft held for sale | AirCraft			1
CRJ900 CRJ200 Aircraft [Member]
Long Lived Assets Held For Sale [Line Items]
Assets held for sale		$ 112,000	$ 112,000
United Airlines Inc [Member]
Long Lived Assets Held For Sale [Line Items]
Number of spare engines to be sold | Engine	20	20
Number of engine sold | Engine		20	30
Gain on the sale of engines		$ 6,700	$ 7,300
Gross proceeds from sale of asset	$ 53,700	53,700
Proceeds from sale of asset	$ 26,900	$ 26,900
Number of aircraft sold | Engine			30
United Airlines Inc [Member] | Engine Sale Agreement [Member]
Long Lived Assets Held For Sale [Line Items]
Number of engine sold | Engine	30	30

Balance Sheet Information - Sum

Balance Sheet Information - Summary of Certain Significant Amounts Included in Condensed Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Expendable parts and supplies, net:
Expendable parts and supplies	$ 38,123	$ 31,913
Less: obsolescence and other	(9,392)	(5,198)
Expendable parts and supplies, net	28,731	26,715
Prepaid expenses and other current assets:
Prepaid aviation insurance	3,176	2,618
Prepaid vendors	143	1,310
Prepaid other insurance	1,290	1,268
Lease incentives	337	352
Prepaid fuel and other	1,418	1,068
Prepaid expenses and other current assets	6,364	6,616
Property and equipment, net:
Property and equipment-gross	1,050,508	1,270,563
Less: accumulated depreciation	(340,814)	(405,309)
Property and equipment-net	709,694	865,254
Other assets:
Investments in equity securities	18,187	15,178
Lease incentives	990	1,097
Contract asset	9,149
Other	515	15
Other assets	28,841	16,290
Other accrued expenses:
Accrued property taxes	4,682	5,866
Accrued interest	5,247	2,882
Accrued vacation	6,832	4,746
Accrued lodging	4,181	3,795
Accrued maintenance	638	1,453
Accrued liability on government payroll program		2,967
Accrued simulator costs	931	1,045
Accrued employee benefits	1,331	1,679
Accrued fleet operating expense	504	1,606
Short term lease incentive liability	97	97
Other	2,278	2,864
Other accrued expenses	26,721	29,000
Other noncurrent liabilities:
Warrant liabilities	25,225	25,225
Lease incentive obligations	1,050	1,050
Long-term employee benefits	610	1,123
Other	1,821	1,821
Other noncurrent liabilities	28,706	29,219
Aircraft and Other Flight Equipment [Member]
Property and equipment, net:
Property and equipment-gross	1,041,056	1,260,143
Other Machinery and Equipment [Member]
Property and equipment, net:
Property and equipment-gross	$ 9,452	$ 10,420

Balance Sheet Information - Add

Balance Sheet Information - Additional Information (Detail) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) shares	Jul. 31, 2021 USD ($)	Jun. 30, 2023 USD ($) Engine	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) AirCraft	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Feb. 28, 2022 USD ($)	Feb. 28, 2021 USD ($)
Condensed Balance Sheet Statements Captions [Line Items]
Depreciation expense			$ 15,300	$ 19,300	$ 46,900	$ 59,900
Estimated initial equity warrant asset value									$ 16,400
Estimated initial warrant asset value								$ 3,200
Net gain/(loss) on investments in equity securities			2,900	$ (3,900)	3,300	(12,600)
Aggregate carrying amount of investments in equity securities			18,200		18,200		$ 15,200
Investments without readily determinable fair value			$ 8,800		8,800		$ 9,000
Asset impairment					50,951	$ 39,475
Heart Aerospace Incorporated [Member] | Forward Purchase Contract [Member] | Preferred Stock [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Purchase of preferred stock		$ 5,000
Initial investment in preferred stock measured at cost		$ 5,000
Class A [Member] | Archer Aviation, Inc. [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Stock issued during period, Shares | shares	500,000
Stock issued during period, Value	$ 5,000
Total grant date value, Additional warrant to purchase shares	$ 5,600
CRJ-900 [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Impairment of intangible asset					$ 3,700
Number of aircraft held for sale			7		21
Asset impairment			$ 30,500
CRJ-900 [Member] | RASPRO Aircraft Lease Agreement [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Number of aircraft held for sale | AirCraft					7
CRJ-900 [Member] | Export Development Canada Aircraft Lease Agreement [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Number of aircraft held for sale | AirCraft					7
CRJ-900 [Member] | RASPRO and Export Development Canada Aircraft Lease Agreement [Member]
Condensed Balance Sheet Statements Captions [Line Items]
Impairment loss related to the held for sale aircraft			$ 30,500		$ 47,200

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Value and Estimated Fair Value of Long-term Debt and Finance Leases, Including Current Maturities (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Long-term debt and finance leases, including current maturities, carrying value	$ 577,533	$ 615,310
Long-term debt and finance leases, including current maturities, fair value	$ 534,400	$ 541,700

Long-Term Debt, Finance Lease_3

Long-Term Debt, Finance Leases, and Other Borrowings - Schedule of Long-term Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	$ 577,533	$ 615,310
Less unamortized debt issuance costs	(5,745)	(8,303)
Less notes payable warrants	(5,506)	(7,272)
Net long-term debt, including current maturities	566,282	599,735
Less current portion, net of unamortized debt issuance costs	(124,341)	(97,218)
Net long-term debt	441,941	502,517
Revolving credit facility quaterly collateralized by underlying equipment and investments through two thousand twenty eight [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	30,630	15,630
Senior and Subordinated Notes Payable to Secured Parties, Due in Monthly Installments Collateralized by the Underlying Aircraft Through 2027 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	67,206	73,850
Notes Payable to Secured Parties, Due in Semi Annual Installments Collateralized by the Underlying Aircraft Through 2028 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	120,053	131,010
Notes Payable to Secured Parties, Due in Quarterly Installments Collateralized by the Underlying Aircraft Through 2028 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	94,571	106,865
United Bridge Loan Quaterly Collateralized By Underlying Equipment And Investments Through Two Thousand Twenty Four [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	2,622
Other Obligations Due to Financial Institutions, Monthly or Quarterly Collateralized by the Underlying Equipment, Due 2022 Through 2031 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	72,657	18,038
Notes Payable to Financial Institution, Due in Monthly Installments Collateralized by the Underlying Equipment, Through 2024 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	1,869	26,758
Notes Payable to Financial Institution, Due in Monthly Installments Secured by Flight Equipment, Through 2023 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities		2,000
Notes Payable to Financial Institution, Quarterly, Through 2027 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	144,400	204,947
Notes Payable to Financial Institution, Due in Monthly Installments Collateralized by the Underlying Equipment, Through 2027 [Member]
Debt Instrument [Line Items]
Gross long-term debt, including current maturities	$ 43,525	$ 36,212

Long-Term Debt, Finance Lease_4

Long-Term Debt, Finance Leases, and Other Borrowings - Schedule of Long-term Debt (Parenthetical) (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Jun. 30, 2023	Sep. 30, 2022
Revolving credit facility quaterly collateralized by underlying equipment and investments through two thousand twenty eight [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2028	2028
Long term debt interest rate description	quarterly interest based on SOFR plus interest spread at 4.50
SOFR [Member] | Revolving credit facility quaterly collateralized by underlying equipment and investments through two thousand twenty eight [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	4.50%
SOFR [Member] | Maximum [Member] | Revolving credit facility quaterly collateralized by underlying equipment and investments through two thousand twenty eight [Member]
Debt Instrument [Line Items]
Incentive recieved	$ 15
Senior and Subordinated Notes Payable to Secured Parties, Due in Monthly Installments Collateralized by the Underlying Aircraft Through 2027 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2027	2027
Long term debt interest rate description	due in monthly installments, interest based on LIBOR plus interest spread at 2.71%
Senior and Subordinated Notes Payable to Secured Parties, Due in Monthly Installments Collateralized by the Underlying Aircraft Through 2027 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	2.71%
Notes Payable to Secured Parties, Due in Semi Annual Installments Collateralized by the Underlying Aircraft Through 2028 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2028	2028
Long term debt interest rate description	due in semi-annual installments, interest based on LIBOR plus interest spread at 4.75% to 6.25%
Notes Payable to Secured Parties, Due in Semi Annual Installments Collateralized by the Underlying Aircraft Through 2028 [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	4.75%
Notes Payable to Secured Parties, Due in Semi Annual Installments Collateralized by the Underlying Aircraft Through 2028 [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	6.25%
Notes Payable to Secured Parties, Due in Quarterly Installments Collateralized by the Underlying Aircraft Through 2028 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2028	2028
Long term debt interest rate description	due in quarterly installments, interest based on LIBOR plus interest at spread 2.20% to 2.32% for senior note & 4.50% for subordinated note
Notes Payable to Secured Parties, Due in Quarterly Installments Collateralized by the Underlying Aircraft Through 2028 [Member] | LIBOR [Member] | Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	4.50%
Notes Payable to Secured Parties, Due in Quarterly Installments Collateralized by the Underlying Aircraft Through 2028 [Member] | LIBOR [Member] | Minimum [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	2.20%
Notes Payable to Secured Parties, Due in Quarterly Installments Collateralized by the Underlying Aircraft Through 2028 [Member] | LIBOR [Member] | Maximum [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	2.32%
Notes Payable to Financial Institution, Due in Monthly Installments Collateralized by the Underlying Equipment, Through 2024 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2024	2024
Long term debt interest rate description	due in monthly installments, interest based on LIBOR plus interest spread at 3.10%
Notes Payable to Financial Institution, Due in Monthly Installments Collateralized by the Underlying Equipment, Through 2024 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	3.10%
Other Obligations Due to Financial Institutions, Monthly or Quarterly Collateralized by the Underlying Equipment, Due 2022 Through 2031 [Member]
Debt Instrument [Line Items]
Long term debt interest rate description	monthly and/or quarterly interest due from 2022 through 2031
Other Obligations Due to Financial Institutions, Monthly or Quarterly Collateralized by the Underlying Equipment, Due 2022 Through 2031 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2022	2022
Other Obligations Due to Financial Institutions, Monthly or Quarterly Collateralized by the Underlying Equipment, Due 2022 Through 2031 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2031	2031
Notes Payable to Financial Institution, Due in Monthly Installments Secured by Flight Equipment, Through 2023 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2023	2023
Long term debt interest rate description	due in monthly installments, plus interest spread at 5.00%
Notes Payable to Financial Institution, Due in Monthly Installments Secured by Flight Equipment, Through 2023 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	5%
Notes Payable to Financial Institution, Quarterly, Through 2027 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2027	2027
Long term debt interest rate description	quarterly interest based on LIBOR plus interest spread at 3.50%
Notes Payable to Financial Institution, Quarterly, Through 2027 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	3.50%
Notes Payable to Financial Institution, Due in Monthly Installments Collateralized by the Underlying Equipment, Through 2027 [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2027	2027
Long term debt interest rate description	due in monthly installments, interest based on fixed interest of 7.50%, through 2027
Notes Payable to Financial Institution, Due in Monthly Installments Collateralized by the Underlying Equipment, Through 2027 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	7.50%
United Bridge Loan Quaterly Collateralized By Underlying Equipment And Investments Through Two Thousand Twenty Four [Member]
Debt Instrument [Line Items]
Long term debt interest rate description	due in quarterly installments based on SOFR plus interest spread at 4.50
United Bridge Loan Quaterly Collateralized By Underlying Equipment And Investments Through Two Thousand Twenty Four [Member] | SOFR [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2024	2024
Long term debt, basis spread on variable rate	4.50%

Long-Term Debt, Finance Lease_5

Long-Term Debt, Finance Leases, and Other Borrowings - Schedule of Principal Maturities of Long-term Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Long Term Debt By Maturity [Abstract]
2023 (remainder of)	$ 23,893
2024	122,194
2025	70,222
2026	219,302
2027	89,200
Thereafter	52,721
Long-term debt	$ 577,533	$ 615,310

Long-Term Debt, Finance Lease_6

Long-Term Debt, Finance Leases, and Other Borrowings - Additional Information (Detail)			1 Months Ended		3 Months Ended	9 Months Ended
	Dec. 27, 2022 USD ($)	Oct. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2022	Dec. 31, 2021 USD ($)	Dec. 31, 2022	Jun. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2020 USD ($)	Apr. 09, 2020 $ / shares
Debt Instrument [Line Items]
Property and equipment-gross						$ 1,050,508,000	$ 1,270,563,000
Long-Term Debt						566,282,000	$ 599,735,000
Warrants of common stock exercise price | $ / shares									$ 3.98
Treasury Loan [Member] | Maximum [Member]
Debt Instrument [Line Items]
Calculated collateral coverage ratio		1.6
Minimum collateral coverage ratio covenant			1.55
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				$ 35,300,000
Secured term loan facility, maximum borrowing capacity				$ 54,000,000
Debt instrument, maturity date				Dec. 31, 2027
Long term debt, fixed interest rate			7.50%		7.50%
United Capacity Purchase Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	3.50%
Revolving loan	$ 10,500,000
Covenant capping restricted payments	5,000,000
Revolving commitments	$ 30,700,000
Rental coverage ratio	1
United Capacity Purchase Agreement [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Amount required						15,000,000
United Capacity Purchase Agreement [Member] | Revolving Credit Facility [Member] | SOFR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	4.50%
United Capacity Purchase Agreement [Member] | United [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amount funded by company						25,500,000
Equipment Notes [Member]
Debt Instrument [Line Items]
Long-Term Debt						120,100,000
Secured Term Loan Facility [Member] | Loan Agreement [Member]
Debt Instrument [Line Items]
Secured term loan facility, maximum borrowing capacity		$ 200,000,000
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
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						$ 729,800,000

Loss Per Share - Calculations o

Loss Per Share - Calculations of Net Loss Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share And Equity [Abstract]
Net income (loss)	$ (47,560)	$ (35,122)	$ (9,090)	$ (9,985)	$ (42,783)	$ (14,274)	$ (91,771)	$ (67,042)
Basic weighted average common shares outstanding	40,688			36,183			38,986	36,064
Diluted weighted average common shares outstanding	40,688			36,183			38,986	36,064
Net loss per share attributable to common shareholders
Basic	$ (1.17)			$ (0.28)			$ (2.35)	$ (1.86)
Diluted	$ (1.17)			$ (0.28)			$ (2.35)	$ (1.86)

Loss Per Share - Number of Weig

Loss Per Share - Number of Weighted-Average Potentially Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share (Detail)	9 Months Ended
	Jun. 30, 2022 shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net income (loss) per share	1,153
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	1,011
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	142

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - $ / shares	Jun. 30, 2023	Sep. 30, 2022	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 Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Income Taxes [Line Items]
Effective tax rate (ETR) from continuing operations	5.50%	19.90%	5.90%	22.10%
State net operating loss carryforwards					$ 5.2
Domestic Tax Authority [Member] | 2027-2038 [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					591.4
State and Local Jurisdiction [Member] | 2023-2043 [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					$ 247
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					2023
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					2043

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2023	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested share-based compensation arrangements	$ 2,700						$ 2,700
Unrecognized compensation cost, period for recognition							1 year 4 months 24 days
Share-based compensation expense	$ 600			$ 700			$ 1,900	$ 2,100
Amounts remitted for employee withholding taxes							$ 346	$ 414
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld	163,920	29,276	847	116,455	13,421	2,275
Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period							1 year
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amounts remitted for employee withholding taxes	$ 300			$ 400
Restricted Stock Units [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld	163,920			132,151
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 - Sche

Share-Based Compensation - Schedule of Restricted Share Activity (Detail) - Restricted Stock [Member]	9 Months Ended
	Jun. 30, 2023 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested, Beginning Balance | shares	1,172,493
Number of Shares, Granted | shares	483,723
Number of Shares, Vested | shares	(553,755)
Number of Shares, Forfeited | shares	(220,533)
Number of Shares, Unvested, Ending Balance | shares	881,928
Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance | $ / shares	$ 4.43
Weighted-Average Grant Date Fair Value, Granted | $ / shares	2.43
Weighted-Average Grant Date Fair Value, Vested | $ / shares	4.61
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	3.39
Weighted-Average Grant Date Fair Value, Unvested, Ending Balance | $ / shares	$ 3.65

Employee Stock Purchase Plan -

Employee Stock Purchase Plan - Additional Information (Detail) - 2019 ESPP [Member] - shares	9 Months Ended	51 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ordinary shares, discount rate	10%
Number of ordinary shares issued	52,278	356,415
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%
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%
Number of ordinary shares issued	500,000

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 30, 2023 USD ($) AirCraft	Dec. 31, 2022 USD ($) AirCraft	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) AirCraft	Jun. 30, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Number of leased aircraft	18			18
Aggregate rental expense under all operating aircraft, equipment and facility leases | $	$ 3,557		$ 10,845	$ 14,252	$ 33,070
Weighted average remaining lease term Operating leases	6 years 2 months 12 days			6 years 2 months 12 days
Weighted average discount rate Operating leases	5.30%			5.30%
RASPRO Aircraft Lease Agreement [Member]
Lessee, Lease, Description [Line Items]
Number of aircraft lease terminated		15
Buyout pricing | $		$ 25,000
RASPRO Aircraft Lease Agreement [Member] | CRJ-900 Aircraft [Member]
Lessee, Lease, Description [Line Items]
Number of leased aircraft		15

Leases - Components of Lease Co

Leases - Components of Lease Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Leases [Abstract]
Operating lease costs	$ 1,283	$ 9,534	$ 7,259	$ 28,678
Variable and short-term lease costs	998	1,311	3,121	4,392
Interest expense on finance lease liabilities	230		734
Amortization expense of finance lease assets	1,046		3,138
Total lease costs	$ 3,557	$ 10,845	$ 14,252	$ 33,070

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - Forward Purchase Contract [Member] - USD ($)	Jul. 31, 2021	Feb. 28, 2021
Heart Aerospace Incorporated [Member] | Maximum [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Purchase commitment amount	$ 1,200,000,000
eVTOL Aircraft [Member] | Archer Aviation, Inc. [Member]
Purchase Commitment Excluding Longterm Commitment [Line Items]
Purchase commitment amount		$ 200,000,000