Spirit Airlines filed for Chapter 11 bankruptcy in November 2024 and ceased operations shortly after, ending two decades of ultra-low-cost flying in the United States. The collapse was not sudden. It was the terminal stage of a business model that depended on razor-thin margins, a fee-heavy structure passengers increasingly resented, and a fleet expansion strategy that left the airline overextended when demand softened. The failed merger with Frontier in 2022, followed by the blocked acquisition by JetBlue in 2024, stripped Spirit of its two most viable exits.