Segment Reporting - Reportable Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Segment Reporting [Line Items]
Revenues		$ 17,672	$ 8,918	$ 42,463	$ 24,483
General and administrative	[1]	50,007	30,380	140,831	86,241
Research and development	[1]	90,536	56,371	304,640	170,484
Loss from operations		(127,804)	(80,574)	(418,879)	(237,912)
Unallocated items:
Depreciation and amortization				19,369	16,314
Stock-based compensation		11,055	5,205	49,145	16,819
Warrant expense				17,091	308
Net loss		(119,119)	(437,214)	(390,181)	(595,909)
Development and Manufacturing Electric Aircrafts
Segment Reporting [Line Items]
Revenues		17,672	8,918	42,463	24,483
Cost of revenues		4,720	2,667	15,176	5,484
Gross profit		12,952	6,251	27,287	18,999
Pre-production manufacturing		36,247	25,673	127,363	80,655
General and administrative		37,723	19,290	99,809	55,830
Research and development		29,721	24,348	88,039	71,928
Other segment items		6,710	4,515	16,581	11,274
Loss from operations		(97,449)	(67,575)	(304,505)	(200,688)
Unallocated items:
Depreciation and amortization		6,896	5,794	19,369	16,314
Stock-based compensation		11,055	5,205	49,145	16,819
Warrant expense		5,760	308	17,091	308
Other unallocated items		(2,041)	358,332	71	361,780
Net loss		$ (119,119)	$ (437,214)	$ (390,181)	$ (595,909)

[1] Includes related party amounts of $5,760 and $308 attributable to warrant expense (research and development) and $75 and $0 (general and administrative) for the three months ended September 30, 2026 and 2025, respectively. Includes related party amounts of $17,091 and $308 attributable to warrant expense (research and development) and $298 and $(140) (general and administrative) for the nine months ended September 30, 2026 and 2025, respectively (see Note 12).