Boeing and Emirates have announced the first orders of the Farnborough air show, the world's largest air show.
In a $US9.1 billion deal , Emirates will buy 30 Boeing 777 aircraft. Earlier reports had suggested that the airline would order 20 planes.
Chief executive Tim Clark says Emirates is getting a good bargain and he will be able to fill them.
Airbus has also received an order for 51 A320 jets from US group Air Lease Corporation, worth $US4.4 billion.
The leasing arm of GE also ordered 100 planes - 60 from Airbus and 40 from Boeing for $US8 billion.
Leasing firms, which lend planes to airlines, are the first to flee the market when business declines, and the first to come back when activity improves.
The resurgence of aircraft leasing confidence is seen as being an important vote of confidence in the industry.