SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Advance deposit required, term			2 months
Contract liabilities	$ 11,800		$ 11,800		$ 2,800
Revenue	40,269	$ 3,654	44,866	$ 15,933
Aircraft sales
Disaggregation of Revenue [Line Items]
Revenue	38,150	0	38,150	5,710
Aircraft management revenue
Disaggregation of Revenue [Line Items]
Revenue	1,803	3,646	6,171	10,215
Subscription
Disaggregation of Revenue [Line Items]
Revenue	$ 316	$ 8	$ 545	$ 8