Carrier files for Chapter 11 protection.
American Airlines has filed for Chapter 11 bankruptcy protection.
American follows Delta, United, Continental and U.S. Airways as the latest major carrier to go through bankruptcy.
American executives have promised to use the time to cut costs.
They say it's the expense of labor that presents the biggest challenge, because contracts force the airline to spend at least $600 million more per year than other airlines.
Negotiations to lower those costs are stalled.
Workers are concerned that American will use bankruptcy to terminate pension plans.
American also says the 240,000 passengers who fly the airlines each day will not be impacted by the bankruptcy filing.