I'm a bit of an airplane junkie and have been to several aviation museums (Air & Space at the Mall, Intrepid in NYC, Pima Air & Space in Tucson, even the Kalamazoo Air Zoo.) As such, I did find myself in a bit of a "Same old, same old" while walking the huge hangars, that is until I got to the Space Shuttle Discovery. The term "awe-inspiring" is often overused, but the Shuttle is absolutely awe-inspiring. For one thing it is massive. And you can get very up close--not quite kick the tires close, but still it in the center of the hanger with plenty of room to walk all the way and see every nook and cranny. Also, the Smithsonian has displayed it in nearly the same condition as it landed, you can see the soot on the sides, the scarring on the tiles, it feels very "real."
The open-ness of the Discovery and it's display area in some respects highlights my reaction to the rest of the museum. They have hundreds of airplanes from around the word, but they seemed a bit crowded together. You could walk around at ground level or on various catwalks, but it still seemed crowded and a bit haphazard.
This was particularly a factor with the Enola Gay. Several years ago, the Enola Gay's forward fuselage including the cockpit and bomb bay were displayed at the Air & Space Museum in the Mall (this was before the Udvar-Hazy Center was opened and before the Enola Gay was fully restored.) There was a platform to walk up and look into the cockpit and you could walk under the plane and look up into the bomb bay and see the special apparatus they installed to handle The Bomb. Now, you just walk around on the ground or catwalk and can't really see anything that relates the history the way the old display did. I've seen other B-29's at aviation museums and if you didn't know this was THE Enola Gay, you would not see anything unique. I'd have liked to have had more opportunities to get up close--it would have been great to look into the cockpit or seating area of the Concorde, for example, or walk underneath the SR-71.
I will suggest making a point to go to the catwalk overlooking the restoration area. That was a highlight, as was the observation tower which overlooks Dulles Airport.
I'll also agree that parking is way overpriced and not in keeping with the "Free to the people" spirit of the Smithsonian.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.