The font used on Air Force One is usually said to be Palatino (for example, http://typophile.com/node/19363), but it doesn't really look like Palatino to me. For instance, the serifs in Palatino are flat vertical or horizontal lines, while the serifs in the AF1 font are at a 45 degree angle (except in the arms of the E and F) and look like arrowheads. Is it a custom US government version of Palatino, or is it some other font completely?
The attachment is a portion of the full photo, which can be found at http://www.af.mil/shared/media/photodb/photos/021126-O-9999G-023.jpg



