American Airlines said on Monday that it had placed an order for 260 new planes in roughly equal numbers from Airbus, Boeing and Embraer. It is the airline’s largest aircraft order since 2011 and reflects the strength of demand for air travel.

The order consists of 85 Airbus A321neo planes, 85 Boeing 737 Max 10 jets and 90 smaller Embraer E175 aircraft. Boeing’s equal standing in the deal suggests that American remains confident in the manufacturer after a panel blew out from a Max 9 plane during a Alaska Airlines flight in January. That episode resulted in no major injuries but reignited concerns about the safety and quality of Boeing planes.

The airline’s chief financial officer, Devon May, told reporters in an interview on Monday that American had faith that Boeing would improve quality after a preliminary federal investigation suggested that the Alaska Airlines plane might have left Boeing’s factory without bolts critical to securing the panel.

“We know what their goals are: They are going to improve quality,” Mr. May said. “They are going to continue to deliver a safe product. And that’s our expectation.”

The Boeing deal includes an existing order for 30 smaller Max 8 jets, which were upgraded to the Max 10. That larger plane, which has not yet received regulatory approval, can seat about 200 passengers.

American does not expect to receive its first Max 10 planes until 2028, Mr. May said. The airline expects Boeing will be able to deliver those jets, but if the manufacturer fails to, Mr. May said, American has made arrangements to replace those deliveries with other Max models or Airbus planes.

American’s A321neo planes typically seat about 200 passengers, too.

The Embraer planes are a workhorse of American’s regional subsidiaries, which typically use the jets for shorter trips, often between smaller airports or from those locations to hub airports. The E175 typically seats about 76 passengers in economy and premium classes.

Embraer, the third-largest plane manufacturer, is based near São Paulo, Brazil, and Airbus, the largest, has its headquarters in Toulouse, France. Boeing, the second biggest, is based in Arlington, Va.

“Over the past decade, we have invested heavily to modernize and simplify our fleet, which is the largest and youngest among U.S. network carriers,” American’s chief executive, Robert Isom, said in a statement. “These orders will continue to fuel our fleet with newer, more efficient aircraft so we can continue to deliver the best network and record-setting operational reliability for our customers.”

American said the planes would help it achieve twin goals of flying bigger aircraft within the United States and on shorter routes as well as offering more premium seats, which are much more profitable and increasingly in demand in recent years. The airline said it would also upgrade existing Airbus A319 and A320 planes starting in 2025, expanding first class, adding power at every seat and installing larger overhead bins.

The order announced on Monday is the largest placed by any U.S. airline since 2021, when United Airlines announced plans to buy 200 planes from Boeing and 70 from Airbus. American’s last large plane order was in 2011, when it bought 260 Airbus planes and 200 Boeings.