United Airlines purchased 270 new Boeing and Airbus aircraft. This is the largest combined order in the airline's history and the biggest by an individual carrier in the last decade. The company expects to introduce more than 500 new, narrow-body aircraft in the next several years: 40 in 2022, 138 in 2023 and as many as 350 in 2024 and beyond. 

The order includes 50 737 MAX 8s, 150 737 MAX 10s and 70 A321neos.