China and the United States signed a deal on Saturday to increase by more than fourfold the number of commercial and cargo flights between the two countries, starting gradually from August.
The agreement between the US Department of Transportation and the Civil Aviation Administration of China adds 14 new US passenger flights a week this year and raises the total to 249 flights a week in six years from the current limit of 54.
United Airlines and Northwest Airlines each have been awarded a new daily flight under the new agreement, US Transportation Secretary Norman Mineta said.
The deal was short of a so-called "open skies agreement", but could be expanded in two years, he said.
"There is an opener in the year 2006," he told reporters. "We'll see how all this plays out, and so 2006 sort of gives us a snapshot to be able to say 'ok, here's where we are now. What do we do for the balance of the agreement?'"
The agreement allowed Chinese carriers to expand flights to the United States along the same lines.
In August or September the US Department of Transportation would designate a new cargo carrier to be allowed flights to and from China, Mineta said.
US cargo carriers would be permitted to build hubs in China from 2007 and in doing so would be afforded "effectively open skies rights", said Karan Bhatia, US assistant secretary of aviation and international affairs.
By the end of March, a new passenger carrier would be designated for flights to China, and both sides would be able to add either kind of flight in 2006, 2008 and 2010, Bhatia said.
The pact will permit carriers to fly to any city in the other country and unlimited code-sharing between US and Chinese airlines. Previously US carriers were restricted to flying to five Chinese cities and the Chinese could fly to 12 US cities.
Mineta said he expected US passenger carriers to jump at the chance to fly, or add routes, to China because international routes made more money than domestic.
"Because this is such a vast market and has been underplayed up to this point, there is just sort of a latent, pent-up demand," he said.
Northwest was given rights for a new flight from Detroit to Guangzhou, the first US-carrier passenger service to that city, with a stopover in Tokyo. United will operate new non-stop service between Chicago and Shanghai.
The world's biggest airline, AMR Corp's American Airlines, is anxious to serve China and has said it would likely bid to offer service to Shanghai from its Chicago hub.
Flag carrier Air China, China Eastern Airlines Ltd and China Southern Airlines Ltd already fly to the United States.
Hainan Air, the regional carrier part-owned by global financier George Soros, has expressed an interest in flying beyond China's borders, including to the United States.