Emirates Airlines agreed to buy 40 Boeing 787-10s in a deal worth more than $15 billion.
The purchase was announced Sunday at the Dubai Air Show by the largest airline in the Middle East.
Deliveries of the wide-body, twin-engine planes are set to begin in 2022.
Boeing's website says the aircraft typically carries 330 passengers with a range of 11,900 kilometers.
The manufacturer says the 787 is 25 percent more fuel-efficient than the aircraft it replaces.
Also, Azerbaijan Airlines announced a $1.9 billion deal for more 787s, five to carry passengers and two more to haul freight.