F-18 Hornets of the Finnish Air Force fly alongside a U.S. Air Force KC-135 Stratotanker from RAF Mildenhall, England, during aerial refueling over Finland, May 25, 2017. All three aircraft are participating in Arctic Challenge 2017, a multinational exercise encompassing 11 nations and more than 100 aircraft. (U.S. Air Force photo by Tech. Sgt. David Dobrydney)