Kennedy Assassination Air Force One
Wright Patterson AFB, Ohio
You can walk inside JFK's Air Force One (a Boeing VC-137C SAM 26000) -- reconfigured to a single narrow aisle between plexiglass walls -- and stand on the exact spot where LBJ stood as he was sworn in, and see where Jackie sat next to JFK's casket on the flight back from Dallas.
The plane was not retired afterward; it continued as Air Force One for Johnson and Nixon, and then occasionally thereafter for Carter, Reagan, Bush 41, and Clinton. But JFK was its first President, and Jackie was the one who had it painted in the classy colors that all subsequent Air Force Ones have followed.