An F-15E Strike Eagle is refueled by a KC-135 Stratotanker Jan. 14, 2011, above Afghanistan, in support of Operation Enduring Freedom. (U.S. Air Force photo/Master Sgt. Adrian Cadiz)

An F-15E Strike Eagle is refueled by a KC-135 Stratotanker Jan. 14, 2011, above Afghanistan, in support of Operation Enduring Freedom. (U.S. Air Force photo/Master Sgt. Adrian Cadiz)