Aug. 30 (UPI) -- Spirit Airlines announced it filed for bankruptcy, less than six months after emerging from Chapter 11 reorganization. The budget carrier said Friday it is "executing a comprehensive restructuring of the airline to position the business for long-term success." The company filed voluntary petitions for Chapter 11 in the U.S. Bankruptcy Court for the Southern District of New York. After the filing, the South Florida-headquartered airline assured customers the carrier will