Topping off the SECDEF
An Air Force E-4B approaches the boom of a KC-135 Stratotanker, assigned to Fairchild Air Force Base, over the Pacific coast, April 10, 2014. The E-4B serves as the National Airborne Operations Center for the president, secretary of defense and the Joint Chiefs of Staff. In case of national emergency or destruction of ground command control centers, the aircraft provides a highly survivable, command, control and communications center to direct U.S. forces, execute emergency war orders and coordinate actions by civil authorities. (U.S. Air Force photo by Senior Airman Mary O'Dell/Released)