American Airlines will pay its pilots 150% of their hourly rate during the holiday season, as it attempts desperately to cover thousands of flights currently unmanned.

In what is an embarrassing stuff-up for the United States’ largest airline, a scheduling glitch has resulted in a critical shortage of pilots for the later part of December.

It is understood that too many pilots were approved leave for the Christmas season, after heavily front-loading their schedule with flights over the next couple of weeks.

Routes out of New York, Miami, Chicago and Dallas-Fort Worth are said to be affected.

"The airline is a 24/7 op," Dennis Tajer, an American Airlines captain and union spokesman, told CNBC.

"The system went from responsibly scheduling everybody to becoming Santa Claus to everyone.

The system went from responsibly scheduling everybody to becoming Santa Claus to everyone.

"The computer said, ‘Hey ya'll. You want the days off? You got it.'"

American Airlines said in a statement Wednesday that it is "working diligently to address the issue and expect to avoid cancellations this holiday season".

"We have reserve pilots to help cover flying in December, and we are paying pilots who pick up certain open trips 150% of their hourly rate — as much as we are allowed to pay them per the contract," the statement said.

"We will work with the APA (Allied Pilots Association) to take care of our pilots and ensure we get our customers to where they need to go over the holidays."

This follows budget Irish airline Ryanair's offer of a bonus €12,000 to captains who work 10 additional days, as a scheduling error saw more than 2,000 flights cancelled over September and October.