A U.S. Air Force F-15E Strike Eagle refuels in-flight from a KC-135R Stratotanker. A U.S. Air Force F-15E Strike Eagle refuels in-flight from a KC-135R Stratotanker in the skies over Macedonia on March 26, 1999, as the two aircraft fly missions in support of NATO Operation Allied Force. Operation Allied Force is the air operation against targets in the Federal Republic of Yugoslavia. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 354975-H-BET53-364.jpg Photo Gallery