There has never been any confirmation by the military or the White House of escorts for Air Force or Marine one. But that does not mean that one does not exist. If one does exist, it most likely would fall to Air Force guard and reserve units and they would retain what ever call sign was assigned for the mission (ex: Texaco 1,2,3,4). If the escorts were Navy, they would use the call sign assigned to their squadron (ex: VFA-41 is Fast Eagle followed by the number on the aircraft’s nose).