In a statement American Airlines said they're quote "working diligently to address the issues and expect to avoid cancellations this holiday season".
Pilots were notified of the error on Friday.
But it's bad news if you booked it with American Airlines.
APA spokesman Dennis Tajer said another solution would be needed for pilots to give up their planned holidays.
Same-sex marriage passes in Australian Senate But shortly after 1.30pm in the national capital, Canberra, the Senate voted in favour of passing the same-sex marriage Bill. This was despite the fact the majority - 63.6% - of Tasmanians voted in favour of same-sex marriage.
American Airlines is the largest US carrier.
American Airlines didn't say how many flights are affected, but the pilots' union said about 15,000 flights were scheduled without a captain, a co-captain or both.
Now the union is reportedly working with AA to address the shortage, with American offering pilots up to 150 percent of their normal hourly wages to work over the holidays. While American Airlines is offering 1.5 times regular pay for pilots who pick up those trips, the company's jobs website does not appear to say what regular holiday pay is on the airline. "This is a crisis right now, and in that crisis, they've gone solo", he said. As a result, thousands of flights now do not have pilots assigned to fly them during the upcoming critical holiday period.
Reuters reports that as of early Wednesday, the union said American Airlines management had not reached out to talk about how to approach the pilot shortage.
Mumbai attack mastermind Hafiz Saeed walks free
Saeed was placed under house arrest in Lahore, Pakistan , in January, in keeping with Pakistan's antiterrorism laws. Saeed has repeatedly denied involvement but had previously been detained twice briefly following the attacks.