Maintenance workers cover the engine of an American Airlines Group Inc. Boeing Co. 737 Max plane outside of a maintenance hangar at Tulsa International Airport (TUL) in Tulsa, Oklahoma, U.S., on Tuesday, May 14, 2019.

American Airlines has accused the unions representing its mechanics of a purposeful work slowdown to win leverage in contract talks, which it said caused more than 900 flight cancellations over the last two months. Now the airline wants compensation from the unions.

A U.S. federal court in Texas this week issued a permanent injunction against the mechanics unions for the slowdown that American alleged in a suit this spring. A day later, Fort Worth-based American Airlines, said it would seek damages from the unions — the Transport Workers Union of America and the International Association of Machinists and Aerospace Workers — saying they violated earlier court orders to resume usual work levels.

The unions, which represent the airline's more than 12,000 mechanics, have denied the allegations.

The unions have caused "enormous financial losses to American, and untold harm in lost customer good will," American said in its filing Tuesday. It said the amount would be determined at a hearing.