assigned@ (Adds details of the error, airline comment)
NEW YORK, Nov 29 (Reuters) - Thousands of December flights on American Airlines do not yet have pilots scheduled to work because of a system scheduling error, the carrier's pilots union said as it gears up for one of the busiest travel periods of the year.
A glitch in the system that bids for pilots' time off based on seniority is behind the shortage, the Allied Pilots Association union said. The group estimated that more than 15,000 flights from Dec. 17-31 - a critical holiday travel period - were affected.
"Basically there's a crisis at American for manning the cockpits," said Dennis Tajer, a spokesman for the Allied Pilots Association.
The system error was disclosed to pilots on Friday, the union said.
"We are working through this to make sure we take care of our pilots and get our customers where they need to go over the holiday," American Airlines spokesman Matt Miller said on Wednesday.
In an email sent to employees, American had offered pilots extra pay to work certain flights in the busy holiday period, but a grievance filed by the union against management said that the restrictions on overtime pay were a violation of the group's contract.
As of early on Wednesday, the union said management had still not reached out to discuss how best to resolve the shortage.
"I'm watching a 'Grinch that stole Christmas' thing happening. And we don't want to see that happening for our passengers," Tajer said. (Reporting by Alana Wise, editing by G Crosse)