U.S. Air Force Capt. JohnMichael Ayers, 351st Air Refueling Squadron pilot, and U.S. Air Force Capt. Brian Dunn, 351st ARS instructor pilot, prepare a KC-135 Stratotanker for flight back to Son San Juan Air Base, Spain, Oct. 22, 2015, over Spain. The crew refueled F-16 Fighting Falcons from Spangdahlem Air Base, Germany, and a C-130 Hercules from RAF Mildenhall, England, as part of Exercise Trident Juncture. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

U.S. Air Force Master Sgt. Larry Nahalea, 351st Air Refueling Squadron boom operator, refuels an F-16 Fighting Falcon from Spangdahlem Air Base, Germany, Oct. 22, 2015 over Spain. Nahalea refueled nine aircraft during this particular mission as part of Exercise Trident Juncture. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

A U.S. Air Force F-16 Fighting Falcon from Spangdahlem Air Base, Germany, flies over Spain Oct. 22, 2015, for Exercise Trident Juncture. Exercise Trident Juncture is a NATO-led exercise to help enhance military interoperability and team work with NATO allies and partners. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

A U.S. Air Force F-16 Fighting Falcon from Spangdahlem Air Base, Germany, receives fuel from a KC-135 Stratotanker from RAF Mildenhall, England, Oct. 22, 2015, over Spain as part of Exercise Trident Juncture. With approximately 36,000 military personnel from more than 30 nations participating, Exercise Trident Juncture is a NATO-led exercise to help enhance the military interoperability and teamwork with NATO allies and partners. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

U.S. Air Force F-16 Fighting Falcons from Spangdahlem Air Base, Germany, fly in formation, Oct. 22, 2015, over Spain. The aircraft received fuel from a KC-135 Stratotanker from RAF Mildenhall, England, as part of Exercise Trident Juncture. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

A U.S. Air Force MC-130J Commando II from RAF Mildenhall, England, receives fuel from a KC-135 Stratotanker from RAF Mildenhall, England, Oct. 22, 2015, over the Atlantic Ocean. The two aircraft were training in exercise Trident Juncture, an exercise designed to help militaries respond more effectively to regional crises with NATO allies and partners – improving security of borders, ensuring energy security and countering threats of terrorism. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

A U.S. Air Force MC-130J Commando II from RAF Mildenhall, England, takes on fuel from a KC-135 Stratotanker from RAF Mildenhall, England, Oct. 22, 2015, over the Atlantic Ocean. The two aircraft were training in exercise Trident Juncture, an exercise designed to help militaries respond more effectively to regional crises with NATO allies and partners – improving security of borders, ensuring energy security and countering threats of terrorism. (U.S. Air Force photo by Senior Airman Christine Halan/Released)

A U.S. Air Force MC-130J Commando II from RAF Mildenhall, England, prepares to receive fuel from a KC-135 Stratotanker from RAF Mildenhall, England, Oct. 22, 2015, over the Atlantic Ocean. The two aircraft were training in exercise Trident Juncture, an exercise designed to help militaries respond more effectively to regional crises with NATO allies and partners – improving security of borders, ensuring energy security and countering threats of terrorism. (U.S. Air Force photo by Senior Airman Christine Halan/Released)