I have been to many air & space museums and this is the best. All sorts of stuff well displayed. There is a 50 cent shuttle between Dulles Airport and the Museum and free luggage storage (put a quarter in and get it back when you leave). MacDonalds on site.
If you own or manage Smithsonian National Air and Space Museum Steven F. Udvar-Hazy Center, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.