The National Air and Space Museum's Steven F. Udvar-Hazy Center

The Smithsonian had so many huge air and space exhibits that they didn't have room for them at their museum on the National Mall. This center opened in 2003 right next to the Dulles International Airport.

Sweetie was in his element. He once had a pilot's license which he let lapse, but his obsession with aviation is still current. I managed to find plenty to interest me, too. It's just really neat to get to see so many different kinds of aircraft up close... for instance a 202-foot long Air France Concorde. The catwalk makes it possible to see many exhibits from below and above.
The massive space shuttle Enterprise, NASA's 1981 test vehicle dominates the space hanger. It also dominates Pipsqueak. She's the little pink and green dot in the lower center.

Since I find World War II lore fascinating (two of my uncles fought in it), I was particularly thrilled to see the Enola Gay fully restored and reassembled for the first time in more than 40 years. That was the Boeing B-29 Superfortress which dropped the atomic bomb on Hiroshima, Japan on August 6, 1945.
I loved these bomber jackets once worn by World War II fight pilots, one named "Return Ticket" and the other, "Belle of the Brawl".

The PanAm display case was interesting: a Life magazine article from 1968 touting "Newest Stewardess Fad: a Japanese in Every Jet", white gloves for spring and summer and black gloves for fall and winter, and the mandatory girdle, no matter how trim the stewardess... a grooming consultant would do random checks for them.
At the end of the day, we spent about a half hour in the Observation Tower watching the planes land at Dulles.