Boeing has agreed to sell 42 of its new 787 Dreamliner planes to four Chinese airlines in a deal worth $5bn (£2.8bn).
The first 787 Dreamliner should be in service for the 2008 Olympics
The US manufacturer has been in talks with a number of Chinese airlines since January when it agreed an outline deal to supply 60 planes to China.
Monday's agreement comprises sales to Air China, China Eastern Airlines, Shanghai Airlines and Xiamen Airlines.
Production of the 217-seat plane will begin next year and the first delivery is expected to take place in 2008.
Boeing is continuing to negotiate with two other Chinese carriers, Hainan Airlines and China Southern Airlines, about the sale of a further 18 planes.
"Today's signing is a major step forward in bringing the revolutionary 787 Dreamliner airplanes to China," Boeing said in a statement.
"It marks a new era of Boeing-China cooperation reinforcing Boeing as the long-term aviation partner of China."
The aerospace giant reached a broad agreement earlier this year to sell 60 planes to six Chinese carriers for $7.2bn.
Shares in national carrier Air China and China Eastern - which are purchasing 15 planes each -were suspended before the deal was announced.
Rising prosperity and a more open society are encouraging more and more Chinese to take to the skies.
Chinese airlines flew 121 million passengers in 2004, 16% higher than the previous year, and are having to buy more planes to meet demand.
Both Boeing and its main rival, European consortium Airbus, have been increasingly targeting China.
Airbus is also targeting China for future growth
Airbus sold five A350 planes to Chinese airlines earlier this year, while Boeing is expecting Chinese carriers to spend $183bn on orders in the next decade.
Boeing says the 787, which is expected to undertake its maiden flight in 2007, will be more fuel-efficient than other long-haul planes.
It is banking on the success of mid-sized jets such as the 787 to propel its long-term business.
Airbus is focusing instead on much larger aircraft, principally the A380 'super-jumbo'.