Two F-15 Eagle aircraft from Royal Air Force Lakenheath, England, fly in formation next to the KC-135 Stratotanker from which they just refueled, May 19, 2017. The KC-135 is assigned to RAF Mildenhall, England. All three aircraft are supporting Arctic Challenge 2017, a multinational exercise encompassing 11 nations and more than 100 aircraft. (Air Force photo/Tech. Sgt. David Dobrydney)