The boom on a 507th Air Refueling Wing’s KC-135 Stratotanker is at the ready as an E-3 Sentry from the 966th Airborne Air Control Squadron prepares to gain elevation in order to start an aerial refueling training mission over the cloudy skies of St. Louis, Mo., Jan. 3, 2013. (U.S. Air Force photo by Senior Airman Mark Hybers)