ATLANTA - Delta Air Lines Inc. and United Airlines have won two coveted new air routes to China's financial and manufacturing capitals and four other new routes have been proposed for 2009, U.S. Secretary of Transportation Mary Peters said Tuesday.

The announcement was part of an agreement signed in July with China to double the number of daily flights between the U.S. and China over the next five years. The agreement also allows for new cargo flights operating to and from the two nations.

Atlanta-based Delta will fly a route from Atlanta to Shanghai available in April, said Peters, who made the announcement from Delta's giant hub at Hartsfield-Jackson Atlanta International Airport. Delta's flight to China's financial hotspot is the first to China by a U.S. airline from the Southeast.

Chicago-based United will fly a route between Guangzhou — China's manufacturing center — and San Francisco starting in 2008 because of the U.S. city's longtime "personal, cultural and business ties to China," Peters said.

Peters said the new routes "are the best way to break down barriers and misconceptions that too often come between our two countries." She predicted the increased air links between the two countries will improve relations and lower fares.

The transportation secretary also said other U.S.-to-China routes have been proposed for 2009. They include New York to Shanghai for Continental Airlines and Detroit to Shanghai for Northwest Airlines. They also include Chicago to Beijing for American Airlines and Philadelphia to Beijing for U.S. Airways. Those routes are under a public comment period and Peters said she hopes to make a decision in the near future.

Before Tuesday's announcement, four U.S. carriers — American, Continental, Northwest and United — had a total of 10 daily passenger flights to Beijing, Guangzhou and Shanghai.

Washington previously was the closest air link for southern businesses with an eye on China. Atlanta's business officials still are still trying for an Atlanta-to-Beijing route, but the earliest that could be awarded is 2010.

Delta CEO Richard Anderson said Peters' announcement was a "watershed event in terms of opening the Southeast United States to the Chinese marketplace."

He said the company expects to start daily flights by the end of March, provided the two new Boeing 777 aircraft it purchased for the route will be available from the manufacturer on time.

Also on Tuesday, Peters told members of the National Business Aviation Association that U.S. air travel infrastructure needs immediate expansion and technology updates to avoid a transportation crisis.