Federal transportation officials are imposing a cap on daily flights at Chicago O’Hare International Airport for the summer, in an effort “to prevent widespread flight delays” at one of the busiest airports in the country.

The new order, issued by the Federal Aviation Administration (FAA) on Thursday, “will reduce delays and make this busy summer travel season a little easier,” Transportation Secretary Sean Duffy said in a statement.

“If you book a ticket, we want you and your family to have the certainty that you’ll fly without endless delays and cancellations,” Duffy said. He went on to say that “unrealistic schedules were set [at O’Hare] to dramatically exceed what they could handle.” 

The Chicago airport “is the busiest airport in America by flight volume,” according to the Department of Transportation. O’Hare had initially scheduled more than 3,080 flights on its busiest travel days this summer—a nearly 15% increase from last summer. 

The FAA said in its order that that increase “will exceed the airport’s capacity throughout the Summer 2026.” The agency said that American Airlines and United Airlines “have each announced expansion plans” at O’Hare “that potentially could lead to significant Summer 2026 delays due to ongoing construction limiting the airfield’s ability to handle the expected amount of traffic.”

As a result, the FAA is limiting the number of flights per day at the airport to 2,708, meaning that on peak days this summer, O’Hare will have to cut as many as 372 flights per day. On days when there aren’t as many flights planned, fewer flights will have to be taken off the schedule.

This scheduling reduction will go into effect on May 17, and will last until Oct. 24, according to the FAA’s order.

The airport has not yet publicly shared information about what flights the order could impact. O’Hare did not immediately respond to TIME’s request for comment.

United told TIME in a statement that it was grateful to the Department of Transportation and the FAA “for leading the process to find a solution that makes sense for everyone who cares about O’Hare’s success.”

“We are reviewing the FAA order and will share additional information, including any next steps, as soon as our review is complete,” the airline said.

American also thanked the federal transportation agencies in a statement.

“Once implemented, the FAA’s action will improve reliability and reduce delays for customers traveling from, to, and through O’Hare this summer,” the carrier said.

In a memo to its Chicago-based staffers that was shared with TIME, American shared its initial estimates of the impact of the FAA’s order, based on previously published schedules: while American said it will have to cut no more than 40 flights—including those arriving at and departing from O’Hare—per day, it expects that United will have to cut about 200 flights per day during peak times.

United did not share an estimate of the number of its flights that could be impacted by the FAA’s order.

Last summer, only 56% of flights departing out of O’Hare didn’t experience any delays, the FAA said. Similarly, only 58% of the flights arriving at the airport that summer didn’t experience any delays. The agency largely attributed the disruptions to the “extensive construction projects” at the airport, including “rehabilitation work on Taxiways A & B resulting in partial closures, and various taxiway closures paired with new routing to accommodate concrete work west of the main terminal area.”

The FAA said that it doesn’t think it will have to impose scheduling restrictions beyond the end of the summer because it anticipates that there will be “significant progress on airfield construction through the Summer 2026 season.”

“Our number one priority is the safety of the flying public, and that means ensuring airline schedules reflect what the system can safely handle,” FAA Administrator Bryan Bedford said in a statement. “We appreciate the airlines working together with us to reach a responsible level of operations that strengthens safety and delivers a more reliable travel experience for the American public.”