SEGMENT REPORTING - Reportable Segment Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues		$ 35,616	$ 15,092	$ 15,357
Cost of revenues		9,901	4,519	2,025
Operating and other expenses
Research and development	[1]	259,892	206,910	138,273
General and administrative	[1]	138,491	75,883	61,629
Net loss		(745,868)	(275,645)	(175,563)
Development and Manufacturing Electric Aircrafts
Segment Reporting Information [Line Items]
Revenues		35,616	15,092	15,357
Cost of revenues		9,901	4,519	2,025
Operating and other expenses
Research and development		259,892	206,910	138,273
General and administrative		138,491	75,883	61,629
Other segment items		373,200	3,425	(11,007)
Net loss		$ (745,868)	$ (275,645)	$ (175,563)

[1] Includes related party amounts of $6,073, $0 and $0 (research and development) and $1,084, $(2,899) and $(1,441) (general and administrative) as of December 31, 2025, 2024 and 2023, respectively (see Note 14)