A U.S. Air Force pilot looks at a KC-135 aerial refueling aircraft as he refuels his F-16 fighter during...
A U.S. Air Force pilot looks at a KC-135 aerial refueling aircraft as he refuels his F-16 fighter during the U.S.-led Saber Strike exercise in the air over Estonia June 6, 2018. REUTERS/Ints Kalnins