Pro Air was forced to cease operations and file for Federal bankruptcy protection when the FAA revoked its operating license on 18 September. In deciding Pro Air "lacks the qualifications required of the holder of an air carrier certificate", the FAA cited unacceptable laxness in the areas of maintenance, quality control and record-keeping. The struggling Detroit-based carrier appealed against the FAA decision, saying it was "issued erroneously and based on incorrect and outdated information", but still filed for Chapter 11 to prevent the seizure of its three 737-400s during the government-mandated shut-down.
Source: Airline Business