Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Operating revenues:
Contract revenue	$ 94,747	$ 131,582	$ 197,980	$ 250,359
Operating expenses:
Flight operations	36,197	49,329	71,470	101,147
Maintenance	43,539	44,272	90,066	92,899
Aircraft rent	1,324	1,408	2,940	2,612
General and administrative	11,484	11,133	21,003	23,142
Depreciation and amortization	5,955	9,823	13,934	23,116
Asset impairment	46,173	2,659	111,838	43,043
Loss on sale of assets	7,706		54,397	150
(Gain) on extinguishment of debt				(2,954)
Other operating expenses	(379)	1,315	381	4,159
Total operating expenses	151,999	119,939	366,029	287,164
Operating (loss) income	(57,252)	11,643	(168,049)	(36,805)
Other (expense) income, net:
Interest expense	(5,334)	(10,640)	(12,398)	(21,800)
Interest income	24	14	41	28
Gain on investments		7,230		7,230
Unrealized loss on investments, net	(11)	(6,499)	(53)	(4,048)
Gain on debt forgiveness		10,500	4,500	10,500
Other income (expense), net	79	(516)	(2,820)	(359)
Total other (expense) income, net	(5,242)	89	(10,730)	(8,449)
(Loss) income before taxes	(62,494)	11,732	(178,779)	(45,254)
Income tax (benefit)/expense	(3,863)	72	(5,591)	936
Net (loss) income and comprehensive (loss) income	$ (58,631)	$ 11,660	$ (173,188)	$ (46,190)
Net (loss) income per share attributable to common shareholders
Basic	$ (1.42)	$ 0.28	$ (4.19)	$ (1.13)
Diluted	$ (1.42)	$ 0.28	$ (4.19)	$ (1.13)
Weighted-average common shares outstanding
Basic	41,334	41,068	41,333	41,004
Diluted	41,334	41,068	41,333	41,004
Contract Revenue
Operating revenues:
Contract revenue	$ 68,423	$ 113,820	$ 149,101	$ 214,920
Pass Through and Other Revenue
Operating revenues:
Contract revenue	$ 26,324	$ 17,762	$ 48,879	$ 35,439