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

The announcement comes before the busiest travel weekend, Thanksgiving, but the airline assured its customers that the tickets they booked are still active and future fares will also be.

Budget carrier Spirit Airlines has filed for bankruptcy protection after years of financial losses and failed merger attempts. On Monday, the airline said it had filed a Chapter 11 bankruptcy petition after working out terms with bondholders.