FORT WORTH, Texas (CBSDFW.COM/AP) — Fort Worth-based American Airlines says mechanics are defying a court order and continuing a work slowdown that is disrupting flights during the busy summer travel season.

The mechanics’ unions say American is at fault. They say the airline walked away from contract talks, leading to low morale which might affect how quickly mechanics perform their work.

A trial is scheduled for Monday in federal district court in Fort Worth on American’s request for a permanent injunction against the Transport Workers Union and the International Association of Machinists and Aerospace Workers.

The Federal Aviation Administration says it has stepped up monitoring of American. That’s a standard step for the agency during airline labor disputes.

American Airlines jetliners are pictured February 3, 2019 at Miami International Airport in Florida. (Photo by Daniel SLIM / AFP) (Photo credit should read DANIEL SLIM/AFP/Getty Images)

In its complaint, the airline says between February and May 13, the unions’ actions have caused 644 flight cancellations and 270 maintenance delays two hours or longer.

The airline says that affected 125,000 customers, and warns an additional 3,400 passengers each day could be impacted.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)

RELATED STORIES

Video Of Heated Confrontation Between American Airlines’ Mechanics And Airline President Shared

American Airlines Accuses Mechanics Unions of Illegal Slowdown Campaign In Lawsuit