Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (46,190)	$ (44,211)
Adjustments to reconcile net loss to net cash flows provided by (used in) operating activities:
Depreciation and amortization	23,116	31,744
Stock compensation expense	799	1,356
Unrealized loss/(gain) on investments, net	4,048	(416)
Realized gain on investments	(7,230)
Deferred income taxes	493	(3,207)
Amortization of deferred credits	(573)	218
Amortization of debt discount and issuance costs and accretion of interest into long-term debt	5,408	2,828
Asset impairment	43,043	20,462
Loss/(Gain) on sale of assets	150	(549)
(Gain) on extinguishment of debt	(2,954)
(Gain) on debt forgiveness	(10,500)
Other	2,362	1,481
Changes in assets and liabilities:
Receivables	3,603	(5,946)
Expendable parts and supplies	(229)	(231)
Prepaid expenses and other operating assets and liabilities	2,691	110
Accounts payable	(1,007)	(11,685)
Deferred revenue	(10,552)	413
Deferred heavy maintenance, net		(1,382)
Accrued expenses and other liabilities	2,219	(2,672)
Operating lease right-of-use assets and liabilities	(309)	3,051
Net cash provided by (used in) operating activities	8,388	(8,636)
Cash flows from investing activities:
Capital expenditures	(13,192)	(24,530)
Proceeds from sale of aircraft and engines	107,735	86,104
Investment transaction costs	(380)
Refund (payment) of equipment and other deposits	341	227
Net cash provided by investing activities	94,504	61,801
Cash flows from financing activities:
Proceeds from long-term debt	86,855	39,000
Principal payments on long-term debt and finance leases	(203,431)	(97,776)
Debt prepayment costs	(922)
Payments of debt and warrant issuance costs		(917)
Proceeds from issuance of ESPP	48	148
Payment of tax withholding for RSUs	(1)	(73)
Net cash used in financing activities	(117,451)	(59,618)
Net change in cash, cash equivalents and restricted cash	(14,559)	(6,453)
Cash, cash equivalents and restricted cash at beginning of period	36,072	61,025
Cash, cash equivalents and restricted cash at end of period	21,513	54,572
Supplemental cash flow information
Cash paid for interest	16,388	20,880
Cash paid for income taxes , net		26
Operating lease payments in operating cash flows	2,858	6,399
Supplemental non-cash operating activities
Right-of-use assets obtained in exchange for lease liabilities	419	821
Supplemental non-cash financing activities
Finance lease obtained in exchange for lease liability		64,682
Principal payments in exchange for transfer of equity investment	12,610
Principal forgiven	$ 10,500
Accrued capital expenditures		$ 1,900