100th Air Refueling Wing -- A U.S. Air Force KC-135 Stratotanker assigned to the 100th Air Refueling Wing, RAF Mildenhall, England, refueled F-15s assigned to the 48th Fighter Wing, RAF Lakenheath, England, during Exercise Valiant Liberty off the coast of England, March 5, 2020. Valiant Liberty is an agile combat employment exercise which allows U.S. and allied forces to deter, defend and win across the spectrum of conflict.