President George W. Bush returns to Andrews Air Force Base, Md., on Sept. 11, 2001, from Offutt Air Force Base, Neb. The president was in Florida when he learned of the terrorist attack on the Pentagon. According to the Air Mobility Command History Office, tankers refueled fighters providing cover for Air Force One as the president moved from Florida. By Sept. 12, tankers also flew air refueling missions for the E-4B National Airborne Operations Center – the president’s airborne command and control center. (U.S. Air Force Photo/Senior Airman Neal X. Joiner)