Yesterday we reported that Delta has delayed its Detroit-Shanghai service until June 2009. Now Northwest is seeking permission from the Department of Transportation to delay its Seattle-Beijing service.

Aviation week is reporting that, due to a 30 percent drop in US-China bookings, the Delta subsidiary wants to delay the start of the route from March 2009 to March 2010 without losing its rights to the routes.

“Northwest is very disappointed that it will not be able to operate its full schedule of U.S.-China combination services in the upcoming year,” Northwest told the DOT. But the airline added that “China remains of critical strategic importance to the Delta/Northwest network.”

The DOT has granted reduction in service to China to American (Chicago-Beijing), United (San Francisco-Guangzhou ), US Airways (Philadelphia-Beijing), Continental (Newark-Beijing and Newark-Shanghai), and Delta (Atlanta-Shanghai).