"International demand is still fairly soft, but we have a strategic commitment to China and we want to make sure we (fulfill) it," Vahidi said. United ( UAUA) has not set a date to inaugurate the San Francisco-Guangzhou, China, flight it delayed. However, United will restart service from Washington's Dulles airport to Beijing in March, after suspending the service due to seasonality. In its winter schedule, Delta ( DAL) will add a fifth weekly Detroit/Shanghai flight, while replacing 747s with 777s on the route. This year, Delta has added New York/Tokyo, Tokyo/Ho Chi Minh City and seasonal Salt Lake City/Tokyo service. Delta has not said when it will restart Atlanta/Shanghai service, suspended in the fall, or begin Seattle/Beijing service, which it has deferred. Meanwhile, Continental ( CAL) began Newark/Shanghai service in March. As of September, Delta was the leading U.S. carrier to Asia, with 298 weekly flights and 87,252 seats. United was second, with 224 weekly flights and 68,482 seats. Continental had 268 flights and 56,912 flights, while American had 92 flight and 27,724 seats, according to the Official Airline Guide. -- Written by Ted Reed in Charlotte, N.C. .