The 89th Airlift Wing (aka Air Force One, et al) has several planes: a few Gulfstreams (think corporate executive jets - C-20B, C 37A, C-37B), 737 (C-40B), 747 (VC-25A) and 757 (C-32A); I don't know how many of each. AF1 is generally one of the 747s, but as Gary mentioned, any fixed wing aircraft with POTUS aboard uses the designation "Air Force One" (maybe even civilan aricraft?). There is also the airborne command center which I have always called "the white whale" because it's a white 747. There is also an Air Force helecopter squadron at Joint Base Andrews that handles (other) executive and distinguished visitor transportation. They apparently still use Hueys, the two-blade helicopters that gained fame in Viet Nam.
Any Marine Corps aircraft with POTUS aboard is designated "Marine One"; These are usually the big green helicopters (Sikorsky SH-3 Sea King or VH-60N "White Hawk") and are assigned to the 1st Marine Corp Helicopter Squadron at Quantico, VA.
Enough boring facts for today. I got an email from Nikon that the D750s are back in stock, so I should be hearing from the store in the next day or two.
Time to head home.