The best part of the Air and Space Museum...
watching planes land at Dulles Airport from the observation/control tower.
Not that the rest of the museum wasn't interesting (although Princess Sparkley was pretty bored), this was just so up close and cool.
Tip: the museum is free, parking is $15 per car. Jed dropped us off at the gate and I walked in with the kids. Although I wouldn't recommend this on a cold, rainy day in October.