Though not as large as other mueums I've visited, the South Dakota Air & Space Museum has a nice selection of historical aircraft including the B-25J used by General Dwight Eisenhower as a personal transport during WWII. Located at the entrance to Ellsworth Air Force Base, the museum offers a tour of Ellsworth and its sole remaining missile silo. Ellsworth is the home of the B-1 and the 28th Bomber Wing. I had the pleasure of witnessing the take-off of a B-1, a sleek, variable-sweep wing, supersonic bomber, during my tour of the base in September, 2012. It was an impressive sight. Our tour guide, a retired airman, was very knowledgeable and offered a detailed account of the capabilities of the Minuteman missile when we were inside the silo, now used for training only.