United Airlines has placed its biggest aircraft order to date in a bet on travel returning post-pandemic.
Its chief executive Scott Kirby said the purchases would "accelerate our business to meet a resurgence in air travel".
The deal will see older, smaller jets replaced - mostly with Boeing 737 Max planes - between 2022 and 2026.
The bigger planes will carry more passengers on domestic routes and enable the airline to sell more premium seats in first class or with extra legroom.
Like many other airlines, United Airlines struggled as demand for travel was constricted during coronavirus-related lockdowns.
At the height of the crisis, it announced that it would need to furlough up to 36,000 staff.