Presidential Aircraft over the years...
FDR - Pan Am Boeing 314 sea plane 'Dixie Clipper', C-54 Skymaster, C-87A 'Guess Where II', C-54C Skymaster 'The Sacred Cow'.
Truman - VC-118 Liftmaster 'Independence'
Eisenhower - VC-121A 'Columbine II', VC-121E 'Columbine III'
Kennedy, Johnson, Nixon - VC-137C 'SAM 26000' (707) Longest serving Presidential Aircraft
Nixon, Ford, Carter, Reagan - 'SAM 27000' newer version of VC-137C
Reagan, Bush, Clinton, Bush, Obama - VC-25 (747) 'Sam 28000'
Future aircraft will be a Boeing 747-8 according to the USAF.