Hainan Airlines has applied to operate a non-stop flight between Beijing and Seattle in the United States starting next June, sources with the General Administration of Civil Aviation of China (CAAC) confirmed on Saturday.

After the application is approved, the airlines will become the fourth Chinese carrier for flights between China and the United States. The other three are Air China, China Eastern Airlines and China Southern Airlines.

The application follows a recent agreement between China and the United States on doubling the number of passenger flights between the two countries by 2012. Hainan Airlines, China's fourth largest carrier, has applied to operate the Beijing-Seattle route using Airbus A330 planes.

The Airbus airplanes will likely be leased as an interim measure until Hainan Airlines takes delivery of new Boeing widebody jets. In 2005, the company ordered eight 787 Dreamliners. the first plane is scheduled to be delivered in June 2008.

Currently there are no non-stop flights between Seattle and Beijing.

In a related development, another two Chinese airlines, Shanghai Airlines Cargo International and Great Wall Airlines, have applied to operate cargo flights to the United States, the CAAC sources said.

The aforesaid transportation agreement allows 23 daily round-trip flights between China and the United States by 2012, up from the 10 flights at present.

In 2010, the two countries are set to begin negotiations on an "open skies" agreement, which will lift restrictions on commercial air traffic.