OFFUTT AIR FORCE BASE, Neb. - Master Sgt. Dan Bloomquist, a flight engineer with the 1st Airborne Command and Control Squadron, preps an E-4B for flight here during a simulated alert mission. The E-4B is a militarized version of the Boeing 747-200 and serves as the National Airborne Operations Center for the president, secretary of defense and chairman of the Joint Chiefs of Staff. It was delivered to the Air Force for operational use in December 1974 and assumed alert status from the EC-135J 35 years ago this month. (U.S. Air Force photo/Lance Cheung)