The low-fare carrier has struggled to find its footing after its planned merger with JetBlue was blocked by a federal judge.

Spirit Airlines filed for bankruptcy protection Monday after the company struggled with a long run of quarterly losses, failed mergers and looming debt, but it plans to keep flying. Spirit's troubles deepened after the collapse of its $3.

Spirit Airlines, the largest budget carrier in the U.S., filed for Chapter 11 bankruptcy protection Monday. The airline said