Vigilant Shield 17
U.S. Air Force KC-135 Stratotanker pilots with the 912th Air Refueling Squadron from March Air Force Base, Calif., prepare for a refueling mission with Royal Canadian Air Force CF-18s while both units participate in the Vigilant Shield 2017 Field Training Exercise, at Joint Base Elmendorf-Richardson, Alaska, Oct. 20, 2016, This exercise provides crucial training opportunities for numerous military personnel with a variety of aircraft and assets from Canada and the United States to improve interoperability and to demonstrate North American Aerospace Defense Command’s ability to defend North America. (U.S. Air Force Photo by Tech. Sgt. Gregory Brook)