Competition has intensified between four US airlines for rights to a new route to China next year.

The carriers - American Airlines, United Airlines, Northwest Airlines and Continental Airlines - have tried to get public support and convince the US Department of Transportation that their proposed routes will benefit the most consumers.

The US Department of Transportation will decide in December which airline receives a route for daily flights between the two countries beginning next spring, as was agreed to in a 2004 Sino-US deal.

United Airlines, the biggest carrier flying Sino-US routes, said it will be the first to start a nonstop service to China from Washington D.C. if its application is approved.

The carrier has applied to launch a daily direct flight between Washington and Beijing.

It also cited huge travel demand between the two cities when Beijing hosts the Olympic Games in 2008.

American Airlines, which has opened nonstop flights from Shanghai and Beijing to Chicago, applied to operate a daily nonstop service between Beijing and Dallas, Texas - the airline's main hub.

It said it would be the first to offer a direct flight from Dallas to China if approved. The carrier also said it has purchased a Boeing 777 aircraft to service the route.

Northwest Airlines points to China's increasing importance to the US auto industry and applied to fly between Detroit and Shanghai.

It said 95 cities would have relatively simple connections to Detroit with a nonstop flight to Shanghai. That was compared to 48 cities for American, 43 for United and 39 for Continental.

"When you look at the route that would benefit the single largest number of consumers, it's the Detroit route," said Andrea Fischer Newman of Northwest, according to the Monterey County Herald.

Continental Airlines, which applied to open a nonstop service between Shanghai and New York, said last month its flight would serve four times the number of people as American's proposed Dallas-Beijing route.

It said it wants to be the first US carrier to serve Shanghai from Newark, New Jersey, which is across the Hudson River from Manhattan.

The winner may cash in on China's booming demand for air travel, which is expected to grow nine percent per year on the passenger side and 15 percent on the cargo side over the next 20 years.

Passenger traffic between the US and China's mainland totaled 1.15 million in 2004, up from 570,000 in 1999.

The airlines have turned to the Internet to gather support.Northwest, Continental, United and American Airlines appealed to frequent fliers to sign petitions.

Each airline collected more than 100,000 signatures and letters via the Internet that will be submitted to the US Department of Transportation.

Meanwhile, the airlines are holding press conferences in China calling for more support.

American Airlines released a list of 108 members of Congress and 15 governors who support its bid.

"This is far broader public support than other airlines have received," declared Will Ris, a senior vice president and the airline's chief lobbyist in Washington.

United Airlines boasted 110 members of Congress in its corner, including a hometown booster, House Speaker Dennis Hastert, the Associated Press said last week.

United said 28 other countries - even Iran - have service to China from their capitals and so US regulators should approve its bid to fly between Beijing and Dulles International Airport outside Washington.

It also said the Dulles-Beijing route would bring up to US$333 million in economic growth in the Washington region and bring 4,100 jobs.

In another move, it won support from the United States Olympic Committee to file a letter to the US Department of Transportation, saying, "Bridging these two cities will help create the kind of unity that is emblematic of the spirit of the Olympic Games."

The carriers filed applications starting in July. In the applications, they took swipes at each other's plans.

Northwest for instance, said it expects to benefit more than 214,000 passengers in the first year, more than any other applicant. It claimed it would carry 70,000 more passengers than American, 62,000 more passengers than Continental, and 8,000 more passengers than United.

It also said it had received more letters of support than claimed by any other applicant.

American is trying to turn the competition into a two-way race with Continental, complaining that Northwest and United already have far more services to China.