Cover - shares	9 Months Ended
	Sep. 30, 2024	Oct. 25, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-40304
Entity Registrant Name	Frontier Group Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-3681866
Entity Address, Address Line One	4545 Airport Way
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80239
City Area Code	720
Local Phone Number	374-4550
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	ULCC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		225,372,311
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001670076
Current Fiscal Year End Date	--12-31