Cover - shares	9 Months Ended
	Sep. 30, 2025	Dec. 01, 2025
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2025
Document Transition Report	false
Entity File Number	001-42932
Registrant Name	BETA Technologies, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-1276474
Entity Address, Address Line One	1150 Airport Drive
Entity Address, City or Town	South Burlington
Entity Address, State or Province	VT
Entity Address, Postal Zip Code	05403
City Area Code	802
Local Phone Number	281-3623
Title of 12(b) Security	Class A common stock, par value $0.0001
Trading Symbol	BETA
Security Exchange Name	NYSE
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Central Index Key	0001784570
Amendment Flag	false
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2025
Current Fiscal Year End Date	--12-31
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		220,528,649
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		8,501,484