American Airlines is ordering 47 new Boeing jets with a combined list price of US$12.3 billion ($16.9b) to replace some of its oldest planes.
Terms are not being disclosed. Airlines routinely get big discounts on planes.
American is also cancelling an order with Boeing's European rival, Airbus, that was made by US Airways before it merged with American, and delaying delivery of 40 other Boeing planes.
American announced the moves Friday. It ordered two sizes of Boeing's 787, a two-aisle jet. They are scheduled to join American's fleet beginning in 2020.
The first arrivals will replace Boeing 767 jets, and later deliveries starting in 2023 will replace Airbus A330 and older Boeing 777 jets in American's fleet.
American already has 35 787s, which it flies on international routes.