A pararescueman assigned to RAF Lakenheath's 57th Rescue Squadron prepares to be hoisted into an HH-60G Pave Hawk during exercise Joint Warrior 15-1 in Scotland on April 22, 2015. (Erin O'Shea/U.S. Air Force)

Melissa Gonzales, an Air Force Wounded Warrior athlete, shares a moment with her service dog, Bindi, after swimming laps during the fourth day of an introductory adaptive sports and rehabilitation camp at Eglin Air Force Base, Fla., on April 16, 2015. (Samuel King Jr./U.S. Air Force)

A C-130 Hercules takes off at Fort Hunter Liggett, Calif., during Exercise Golden Hydra on Tuesday, March 31, 2015. More than 130 airmen from five wings across Air Mobility Command and the Air National Guard participated in a contingency response exercise March 29 through April 3 at three locations in California. (Matthew Hannen/U.S. Air Force)

A U.S. Air Force CV-22 Osprey prepares to receive fuel from an MC-130 Combat Shadow II during Emerald Warrior 2015 over the Gulf of Mexico on Tuesday, April 28, 2015. (Douglas Ellis/U.S. Air Force)

A C-130 Hercules from the 36th Airlift Squadron, Yokota Air Base, Japan, flies at low altitude with A-10 Thunderbolt IIs from the 25th Fighter Squadron, Osan Air Base, Republic of Korea, on Monday, April 27, 2015, as part of exercise Balikatan 2015. (Nathan Allen/U.S. Air Force)

A U.S. Air Force airman from the 21st Special Tactics Squadron performs a static-line jump during Emerald Warrior 2015 at Camp Rudder, Fla., on April 24, 2015. (Jamal D. Sutter/U.S. Air Force)

U.S. Air Force combat controllers, 21st Special Tactics Squadron, observe an AC-130 Gunship conduct a live-fire mission during Emerald Warrior at Camp Shelby, Miss., on April 22, 2015. (Jonathan Snyder/U.S. Air Force)