Emirates Airlines has ordered 50 long-range Boeing 777 passenger aircraft in a deal worth about $US18 billion.
Emirates has also placed options for more jets, worth another $US8 billion.
The BBC reports the announcement take its orders of the aircraft to 90.
Last year Emirates placed an order for 30 Boeing 777 planes worth $US9.1 billion in a deal announced at the Farnborough airshow in Britain.
The airline is also the largest single customer of the Airbus superjumbo aircraft, the A380, with a purchase list of 90 units.
Boeing delivered 127 commercial airplanes in the third quarter of 2011.
