WASHINGTON - If the National Air and Space Museum on the National Mall is aviation's Mecca, the pilgrimage now has a second site. The Steven F. Udvar-Hazy Center, named for its primary backer, opened adjacent to Dulles International Airport in December, providing a cavernous showcase for the Smithsonian's larger aircraft and space vehicles, as well as many others that couldn't find room in the traditional space. Unlike the Mall site with its sleek, boxy exterior, the new center across the river in nearby Virginia invokes the aviation history inside with its massive hangars and control tower observation deck. Whereas the...