An F-16 Fighting Falcon assigned to the 120th Fighter Squadron, Colorado Air National Guard, flies near the wing of a KC-135 Stratotanker assigned to McConnell Air Force Base, Kan. after being refueled May 10, 2017, over Colorado. Aerial refueling allows aircraft to fly for longer periods of time without needing to land to refuel. (U.S. Air Force photo/Airman 1st Class Erin McClellan)