DALLAS - American Airlines is scrambling to find pilots to operate thousands of flights over the busy Christmas holiday period after a glitch in the system used to schedule crews.

  

A spokesman for the airline said Wednesday that American expects to avoid canceling flights by paying overtime and using reserve pilots.

  

American isn't saying how many flights are affected, but the pilots' union says that about 15,000 flights were scheduled without a captain, a co-pilot or both.

  

A union spokesman calls it a potential crisis.

  

American is the world's biggest airline. It has about 15,000 active pilots and expects to operate more than 200,000 flights in December.