Spirit Airlines ceased all operations on May 2, 2026, becoming the first major U.S. carrier to fully liquidate since Midway Airlines in 2001, following two failed bankruptcy filings.

Spirit Airlines stopped all flight operations at 3:00 AM Eastern on May 2, 2026, after filing for Chapter 11 protection in November 2024 and a second bankruptcy filing on August 29, 2025. The collapse stranded thousands of passengers with no rebooking assistance or interline agreements honored by other carriers.

The airline's cost structure deteriorated sharply: adjusted cost per available seat mile (excluding fuel) rose from 5.67 cents in Q4 2019 to 7.97 cents by full-year 2024, exceeding the approximately five-cent threshold required for ultra-low-cost carrier economics. The airline had accumulated more than 2.5 billion dollars in cumulative losses since the start of 2020.

An analysis by Novo Navis concludes that while causal AI systems can identify airline distress trajectories with greater mechanistic precision than traditional analytics, no production deployment of causal early warning systems existed in the airline industry before Spirit's collapse, and the temporal window for intervention was likely already closed before such systems matured.