Four US airlines this week are intensifying a contest to open the next non-stop route to China, the world's hottest growth market.

On Monday, American, Continental, Northwest and United airlines will submit briefs to the US Department of Transportation (DOT) to boost their bids for the one China route to be approved this year.

The DOT decision is expected to give an economic boost to one of the four US metro areas that would be linked to China by the new air service: Dallas-Fort Worth, Detroit, Washington, DC, or New York City. Of the four, only the New York area now has a non-stop link to China.

The DOT is charged with choosing a route that will best serve the public interest. But that hasn't stopped the airlines from waging intense public lobbying campaigns to try to influence the decision.

Even American Airlines lobbyist Will Ris calls the combined noise level "a little bit out of proportion."

American and United Airlines have launched special websites that let the public sign petitions to the DOT.

All of them have mobilized big-name supporters. United has signed up eight former US trade representatives and former Federal Aviation Administration chief Jane Garvey to push service between Washington and Beijing.

American on Monday will announce it has dozens of members of Congress on its side. Northwest is also in the fray.

Houston-based Continental, which wants to fly from its hub at Newark Liberty Airport to Shanghai, held a news conference this month in New York's Chinatown to build support.

Continental argues New York and Shanghai are the most populous cities in the two nations not linked by non-stop service. Continental's proposed flights would "conveniently link the two largest business centers," says spokeswoman Julie King.

Continental won't be able to make that argument for long. Shanghai-based China Eastern Airlines announced last week it plans Shanghai-New York non-stops starting December 8.

The Chinese mainland, the USA's top Asian trading partner, is seeing double-digit annual growth rates in passenger counts, and air cargo shipments are growing nearly as fast.