Originally Posted by BearX220

That's a C-32 (Boeing 757) in the photo. The president uses it often on shorter trips. SAM (Special Air Mission) can place a bunch of different aircraft at the disposal of the Executive Branch and Cabinet -- not only the 747 and 757 but 737s (C-40s) and Gulfstreams (C-37s). The VP, Secretaries of State and Defense, the First Lady, etc. all use these aircraft. As many have pointed out, you may think "747" when you hear Air Force One, but any SAM aircraft carrying the president is Air Force One.

The interesting question for SAM is how to replace its two VC-25s (747-200s) when they reach the end of their service lives in a few years. They date from the early days of the first Bush administration which means they're going on 25 years old. The Air Force has always specified four-engine aircraft for longhaul over-water presidential transport, but the Boeing 748 and Airbus A380 are the only two candidates, and the 748 is an apparent market dud that may not be on offer much longer.