-25A is one of two Boeing B747-200B aircraft (heavily modified) used by the US Air Force and configured as presidential aircraft.
Air Force One is a call sign - not an aircraft. Any USAF
aircraft with the president on board is "Air Force ONE". President George W. Bush flew on the VC
-25A, the C-32 (B757) KCNW- KELD, the C-40 (B737) KCNW-KEFD and the C-20 (Gulfstream III or IV depending upon the individual aircraft used) KCNW-KDAL; as Air Force ONE at different times.
President Obama has flown to New York on a 'date' with his wife in the C-37 (Gulfstream V) and for vacations with his family on C-20 aircraft. All using the Air Force ONE call sign.
He also flew on a US Navy S-3 Viking - which used the callsign Navy ONE. (President Bush being the only president who has flown supersonic and who was ejection seat qualified during his time in the Guard).
The helicopter which flies the President from the White House to Andrews AFB uses the call sign Marine ONE when the President is aboard.
I'm not aware of a recent President flying on a US Army aircraft - but if he did - it would use the callsign Army ONE.
When President Nixon flew on a commercial United Airlines DC-10 aircraft from Washington DC to Los Angeles - the flight used the call sign Executive ONE.
The Air Force ONE call sign has been used by aircraft without the President aboard when necessary for security purposes - notably President Clinton's March 2000 flight into Pakistan. The call sign being used to divert attention of any spotters or possibly malicious persons away from the aircraft carrying the President.
The Wikipedia article on the VC
-25 is pretty good - http://en.wikipedia.org/wiki/Boeing_VC-25
This is a photo of the 'bedroom' http://en.wikipedia.org/wiki/File:Pr...ate_cabin_aboard_Air_Force_One.jpg[Edited 2012-06-28 07:29:25]
[Edited 2012-06-28 07:32:51]