A C-17 Globemaster III crew prepares an air refueling mission September 27, 2012, at Joint Base Charleston, S.C. (Photo by Airman 1st Class Matthew J. Bruch/U.S. Air Force photo)

Aircrew members admire their MC-130E Combat Talon during the plane's final flight before retirement. The last five MC-130s in the Air Force belong to the 919th Special Operations Wing at Eglin Air Force Base, Fla. (Photo by USAF)

The F-35 Integrated Test Force is completing a series of night flights, testing the ability to fly the jet safely in instrument meteorological conditions where the pilot has no external visibility references. The ITF, which has the lead on all F-35 mission systems testing, is responsible for five of the six night flights. (Photo by Tom Reynolds/Lockheed Martin)

An F-22 Raptor backs away from a KC-135 Stratotanker during a training mission over central New Mexico. The Raptor is assigned to the 49th Fighter Wing at Holloman Air Force Base, NM., and the KC-135 is from McConnell Air Force Base, Kan. (Photo by USAF)

Senior Airman Justin Gordon completes a static line jump at Spangdahlem Air Base, Germany. (Photo by USAF)

Tech. Sgt. Andrew Gravett walks along the top of a C-17 Globemaster III as he does a routine maintenance check at Joint Base Charleston, S.C. The first C-17 to enter the Air Force's inventory arrived at Charleston Air Force Base in June 1993. (Photo by USAF)

Senior Airman Pedro Rodriguez, a combat controller with the 22nd Special Tactics Squadron out of Joint Base Lewis-McChord, Wash., watches as other members of his team land after parachuting 13,000 feet for training. A combat controller's mission is to deploy undetected into combat and hostile environments to conduct special reconnaissance, establish assault zones or airfields, while simultaneously conducting air traffic control, fire support, command, control, and communications and forward air control. (Photo by Senior Airman Andrew Lee/U.S. Air Force photo)

A U.S. Air Force B-52 Stratofortress from the 20th Expeditionary Bomb Squadron at Barksdale Air Force Base, La., leads a formation of two F-16 Fighting Falcons from the 18th Aggressor Squadron, Eielson AFB, Alaska; two Japan Air Self-Defense Force F-2 fighters from the 6th Tactical Fighter Squadron, Tsuiki Air Base, Japan; two U.S. Navy EA-6B Prowlers from Electronic Attack Squadron 136, Carrier Air Wing 5, Naval Air Facility Atsugi, Japan; and a JASDF E-2C Hawkeye from the 601st Squadron, Misawa Air Base, Japan, over Guam during exercise Cope North. The Air Force and JASDF conduct Cope North annually at Andersen Air Force Base, Guam, to increase combat readiness and interoperability. (Photo by Staff Sgt. Jacob N. Bailey/U.S. Air Force photo)

A B-2 Spirit flies over St. Louis's Gateway Arch. (Photo by Tech. Sgt. Justin D. Pyle/U.S. Air Force photo)

USAF aircraft of the 4th Fighter Wing (F-16, F-15C and F-15E) fly over Kuwaiti oil fires, set by the retreating Iraqi army during Operation Desert Storm in 1991. (Photo by USAF)

Utah Air National Guard Airmen conduct air refueling operations with a C-17 Globemaster III assigned to Joint Base Lewis-McCord, Wash., over southern Idaho. The Airmen are assigned to the 151st Air Refueling Wing at Salt Lake City Air National Guard Base, Utah, and support air operations across the western United States. (Photo by USAF)

The Thunderbirds Diamond Formation performs a pass in review manoeuvre during a training sortie over a range in Nevada. (Photo by USAF)

Members of the 191st Air Refueling Squadron conduct refueling operations with a C-17 Globemaster III from Joint Base Lewis-McCord, Wash. Airmen from the 191st ARS routinely support air operations across the western United States from their home station in Salt Lake City, Utah. (Photo by USAF)

Six C-130 Hercules line up before flying a sortie during a readiness week at Yokota Air Base, Japan. The 374th Airlift Wing uses C-130s to support operations in the Pacific. (Photo by USAF)