An Alaska Air National Guard HH-60 Pave Hawk helicopter, assigned to the 210th Rescue Squadron, prepares to land on the flight deck of the amphibious transport dock ship USS Anchorage (LPD 23) in the Cook Inlet off the coast of Anchorage, Alaska, April 30, 2013. The Pave Hawk pilots practiced landing on the USS Anchorage to receive training not readily available in the region. The Anchorage was set to be commissioned in Anchorage May 4, 2013. (DoD photo by Staff Sgt. Zachary Wolf, U.S. Air Force/Released)

F-16 Fighting Falcons demonstrate an ‘Elephant Walk’ as they taxi down the flightline at Kunsan Air Base, South Korea, Dec. 14, 2012. The Elephant Walk was a demonstration of U.S. and South Korean air force capabilities and strength. The F-16 Fighting Falcons are from the 35th and 80th Fighter Squadrons of the 8th Fighter Wing, Kunsan AB, South Korea; the 4th Fighter Squadron of the 388th Expeditionary Fighter Wing at Hill Air Force Base, Utah; and the 38th Fighter Group of the Republic of Korea air force. (U.S. Air Force photo/Staff Sgt. Jonathan Fowler)

A U.S. Air Force C-17 Globemaster III aircraft lands at Nellis Air Force Base, Nev., as three F-15C Eagle aircraft assigned to the 48th Fighter Wing at Royal Air Force Lakenheath, England, hold short of the runway during exercise Red Flag 13-3 Feb. 25, 2013. Red Flag is an advanced aerial combat training exercise held four to six times a year to train pilots from the U.S., NATO and other allied countries for real combat situations. (DoD photo by Lawrence Crespo, U.S. Army/Released)

U.S. Marine Corps MV-22 Osprey aircraft with Marine Medium Tiltrotor Squadron (VMM) 161 land at a forward operating base in Afghanistan Dec. 24, 2012, as the commandant and sergeant major of the Marine Corps visit deployed troops over the Christmas holiday. (DoD photo by Master Sgt. Brenda Varnadore, U.S. Marine Corps/Released)

A U.S. Army UH-60 Black Hawk helicopter with Alpha Company, 5th Battalion, 101st CombatAviation Brigade conducts an engine run-up in the falling snow of a winter storm at Bagram Airfield in the Parwan province of Afghanistan on Dec. 27, 2012. DoD photo by Sgt. Duncan Brennan, U.S. Army. (Released)

U.S. Army Spc. Richard Burton leans out the door of a UH-60 Black Hawk helicopter to get a better view of the ground during a flight mission over Afghanistan’s Kandahar province on Nov. 26, 2012. Burton is a crew chief with the 25th Infantry Division’s 2nd Battalion, 25th Combat Aviation Brigade. DoD photo by Staff Sgt. Brendan Mackie, U.S. Army. (Released)

A U.S. Marine Corps KC-130J Super Hercules aircraft with Marine Aerial Refueler Transport Squadron (VMGR) 352 refuels a French air force Dassault Mirage 2000-5 aircraft during a refueling training mission over Djibouti Nov. 22, 2012. The mission was intended to improve interoperability between U.S. and French forces. (U.S. Air Force photo by Tech. Sgt. Joseph McKee/Released)

U.S. Coast Guard Petty Officer 1st Class Ty Aweau, an Aviation Survival Technician, conducts rescue swimmer training with an aircrew in an HH-65 Dolphin helicopter off Hermosa Beach, Calif., Nov. 16, 2012. (DoD photo by Petty Officer 1st Class Adam Eggers, U.S. Coast Guard/Released)

An X-47B unmanned combat air system (UCAS) demonstrator is hoisted aboard the aircraft carrier USS Harry S. Truman (CVN 75) in Norfolk, Va., Nov. 26, 2012. Sailors aboard the Harry S. Truman were conducting flight deck handling tests with the UCAS. Harry S. Truman was the first aircraft carrier to host test operations for an unmanned aircraft. (DoD photo by Alan Radecki, U.S. Navy/Released)

An A-10 Thunderbolt II pulls up behind a KC-10 Extender to be refueled in Southwest Asia on Sept. 18, 2012. The KC-10 is an advanced tanker and cargo aircraft designed to provide increased global mobility for U.S. armed forces. (U.S. Air Force photo/Master Sgt. Scott MacKay)