The E-4B is one of the so-called Doomsday planes. In the event of a nuclear war, a terrorist attack, an alien invasion or, generally speaking, Armageddon, the U.S. Air Force’s four E-4B planes based at Offutt Air Force Base, Nebraska will be responsible to keep the U.S. Secretary of Defense, the Joint Chiefs of Staff and other top personalities alive whilst Obama would be on board the Air Force One.