American Airlines pilots were able to cancel thousands of flights last night due to a glitch in their scheduling platform, their union stated Saturday. This was a problem for the airline, which is trying to minimize disruptions in an exploding travel season.

American confirmed the issue, and stated that it did not expect the problem would affect its operations during the July Fourth holiday weekend.

The airline released a statement saying that “certain trip trading transactions were allowed to be processed even though it shouldn’t have been”. “We have already restored the vast majority affected trips and don’t anticipate any operational impacts due to this issue.”

The Allied Pilots Association stated earlier that more than 12,000 July flights were without a captain, first officers, or both after pilots dropped their assignments.

Pilots can drop and pick up flights, but it is difficult to find time off during the summer or holidays for airline employees because of high demand.

According to internal statistics, American had over 3,000 scheduled mainline flights on Saturday and were 93% full. However, flights that aren’t staffed add to the strain on airlines.

This glitch happened during a rough start to Fourth of July weekend, when storms and staffing problems caused thousands of U.S. flights delays and hundreds of cancellations.

American Airlines and the pilots’ union are currently in contract negotiations. The airline recently offered almost 17% raises through 2024, which is a breakup. Capt. On Friday, Ed Sicher began a three year term.

Pilots in America have been protesting the grueling schedules of their flights. They want a new contract to address this issue. In recent weeks, Southwest and Delta pilots have taken part in similar protests.

American stated that it had suspended a platform that allowed pilots to modify their schedules as it investigated the problem.

We understand that these tools are critical for pilots, and we are doing our best to get them out as soon as possible. American informed pilots via email that they would provide updates throughout the day as soon as they learn more.

Dennis Tajer, a captain of American Airlines and spokesman for Allied Pilots Association, stated that the company had failed to maintain its IT system properly, creating uncertainty for pilots and passengers.