Airmen from the 37th Bomb Squadron board a bus outside the Deployment Center during a Green Flag exercise at Ellsworth Air Force Base, S.D. More than 130 Ellsworth Airmen traveled to Nellis Air Force Base, Nev., to test their ability to survive and operate in a wartime environment in preparation for future deployments. (U.S. Air Force photo by Airman 1st Class Rebecca Imwalle/Released)