ADMINISTRATION FACES REALITY OF WORLD TRADE.(MAIN)

Byline: DAVID E. SANGER - New York Times

SEATTLE -- What may be the biggest rethinking of U.S. policy toward Asia since the days of Gen. Douglas MacArthur is finally under way, and President Clinton began to outline it last week just inside a giant airplane hangar at Boeing Co.

Boeing is, after all, the country's largest exporter, and as Clinton told a cheering throng, its booming Asian business is a model for companies across America. China alone now buys one of every six of its planes; Asian airlines own half of all the 747s ever made.

But there is a less-discussed price. The fuselage of Boeing's newest jet, still 18 months from delivery, isn't built by Boeing, but by Mitsubishi Heavy Industries at the plant in Nagoya, Japan, that spit out Zero fighter planes for World War II. The Chinese build …