A soldier helps another with her ear protection at the Terningmoen Camp in Elverum, Norway on March 23, 2017. Soldiers demonstrate their skills and tactics during a contract drill as they train to become part of the world's first all-female special forces unit, the Jegertroppen or “hunter troops”. (Photo by Carolina Reid/NBC News)

“The McDonnell Douglas KC-10 Extender is an air-to-air tanker aircraft in service with the United States Air Force derived from the civilian DC-10-30 airliner. The KC-10 was the second consecutive McDonnell Douglas transport aircraft to be selected by the US Air Force following the C-9 Nightingale. The similar KDC-10 is in service with the Royal Netherlands Air Force.”

Photo: A B-52G Stratofortress aircraft takes off with another B-52G close behind. Three cells of six B-52 and KC-10 Extender aircraft will takeoff seconds apart under combat conditions during the minimum interval takeoff exercise. The exercise is a part of an operational readiness inspection by the Strategic Air Command Inspector General Team. (Photo by USAF). 1998

A poster for the IMAX presentation of “The Hunger Games: Catching Fire” (left), and a teaser poster for “The Hunger Games: Mockingjay, Part I”, both created by the Los Angeles-based design firm IGNITION. Both are nominated for the 2014 Key Art Awards in the category of Theatrical Domestic One-Sheet. The Hollywood Reporter's annual competition for the best in film and TV advertising honors some of the most creative imagery used in movie posters. Here is a selection of some of this year's nominees. (Photo by Key Art Awards 2014)

Air National Guard takes to the skies over Puget Sound during Seafair 2015 on Thurs., July 30, 2015 in Seattle, Wash. (Photo by Matt Mills McKnight/AP Images for John Klatt Airshows, Inc.)

John Klatt and the Air National Guard MXS (right) and Mike Wiskus and the Lucas Oil Pitts take to the skies at the Memphis Airshow, on Sat., September 26, 2016 in Millington, Tenn. (Photo by Brandon Dill/Invision for John Klatt Airshows, Inc./AP Images)

Pilots plan a flight manoeuvre with model aircraft at a military air base in Vasylkiv, Ukraine, August 3, 2016. (Photo by Gleb Garanich/Reuters)

The Chicago Air & Water Show is an annual air show held on the shore of Lake Michigan in Chicago, Illinois. The show has been held each year since 1959 and is Chicago's second most popular festival. In 2005, 2,200,000 watched the Chicago Air and Water Show.

A French Air Force Mirage 2000 fighter jet takes off during the close air support (CAS) exercise Serpentex 2016 hosted by France in the Mediterranean island of Corsica, at Solenzara air base, March 17, 2016. Serpentex is an annual exercise that involves joint terminal attack controllers (JTACs) from 12 countries from March 7 to March 25, 2016. (Photo by Charles Platiau/Reuters)