DELTA Air Lines Inc and US Airways Group Inc are seeking regulators' approval to start flying to Beijing under a new aviation agreement.
Delta proposed flying between Atlanta and Beijing, while US Airways applied to fly from Philadelphia, the airlines said on Monday.
American Airlines, United Airlines, Continental Airlines Inc and Northwest Airlines Corp have all asked to expand their existing flights.
United wants to start flights in 2009 between Los Angeles and Shanghai. Northwest is seeking to fly nonstop between its Detroit hub and both Shanghai and Beijing "as soon as possible."
Continental proposes flights between Newark, New Jersey, and Shanghai.
The applications moved the United States Transportation Department a step closer to awarding 56 new flights over the next two years.
A route to China, the world's fastest-growing major economy, can boost an airline's annual revenue by about US$100 million, Bloomberg News said.
"Most of the network carriers want to increase their Pacific operations," Ray Neidl, a New York-based analyst with Calyon Securities, said. "It's a growth area, and China's at the heart of that."