The airlines are canceling 300 flights this week and more are expected next month. They axed the flights to cope with a high number of pilots calling in sick and an increase in maintenance reports filed by flights crews.
American has seen an increase in flight cancelations since early this month.
Earlier this month a federal judge allowed the company to void it pilots union contracts and impose new pay and work rules.
The airline says pilots are calling in sick and there is an increase in maintenance reports filed by crews. This comes after American sent layoff notices to 11,000 employees.
Earlier this week, American said it would cut its schedule through the end of October by up to 2 percent.
"Beginning yesterday and through the weekend, we will have proactively canceled about 300 flights, very selectively, taking out flights that will have the least impact on our customers, to allow more of our resources to be available for the others," said Bruce Hicks, a spokesman for American Airlines.
Each day this week, American has canceled more flights than any U.S. airline, according to flight tracking service FlightAware. By late Wednesday afternoon, American and Eagle had canceled 73 flights, more than the next five airlines combined. They canceled 104 flights on Tuesday and 72 flights on Monday, FlightAware said.
The Associated Press contributed to this report.