The US Smithsonian National Air and Space (NASM) museums are great.
For those that aren’t aware, one of the locations is on the Capitol Mall in Washington, DC and the other - the Steven F. Udvar-Hazy Center - is near the Dulles Airport in Dulles, VA.
The latter has the Space Shuttle Discovery, a Lockheed SR-71 Blackbird, a Concorde… and the Enola Gay.