Ayesha Farooq, 26, Pakistan's only female war-ready fighter pilot watches an airforce jet about to take off at Mushaf base in Sargodha, north Pakistan June 7, 2013. Farooq, from Punjab province's historic city of Bahawalpur, is one of 19 women who have become pilots in the Pakistan Air Force over the last decade – there are five other female fighter pilots, but they have yet to take the final tests to qualify for combat. A growing number of women have joined Pakistan's defence forces in recent years as attitudes towards women change. (Photo by Zohra Bensemra/Reuters)

Fighters from Germany take up position before competing in the Medieval Combat World Championship at Malbork Castle, northern Poland, April 30, 2015. Medieval combat is a full contact sport that revives the foot based tournament fighting of medieval Europe. Countries fight in refereed matches where the objective is to get the opposing team to the floor. There are also duels with polearms, swords and shields where the number of hits landed are scored. The fighters, both male and female, wear heavy armours and weapons, mostly replicas of authentic pieces, and fight following the knights code of conduct. According to organizers, 25 nations from 6 continents are taking part in the Championships, which started on April 30 and will go on until May 3. (Photo by Kacper Pempel/Reuters)

The new Amazon tablet called the Kindle Fire is displayed on September 28, 2011 in New York City. The Fire, which will be priced at $199, is an expanded version of the company's Kindle e-reader that has 8GB of storage and WiFi. The Fire gives users access to streaming video, as well as e-books, apps and music, and has a Web browser. In addition to the Fire, Bezos introduced four new Kindles including a Kindle touch model. (Photo by Spencer Platt/Getty Images)

An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) emerges from a cloud created when it broke the sound barrier in the skies over the Pacific Ocean, July 7, 1999. (Photo by John Gay/US Navy)

A pilot looks up from a U.S. F-22 Raptor fighter as it prepares to refuel in mid-air with a KC-135 refuelling plane over European airspace during a flight to Britain from Mihail Kogalniceanu air base in Romania April 25, 2016. (Photo by Toby Melville/Reuters)

Armed Yemeni children sit in the back of a pick up truck with fighters loyal to Yemen's Saudi-backed President Abedrabbo Mansour Hadi in the Dar saad neighbourhood of the southern Yemeni city of Aden on May 10, 2015, as they continue to battle Shiite Huthi rebels. (Photo by Saleh Al-Obeidi/AFP Photo)

In this Wednesday, August 20, 2014 photo released by Red Bull, Maikel Melero of Spain warms up prior to the fifth stage of the Red Bull X-Fighters World Tour in the South African savanna of Pretoria, South Africa. (Photo by Joerg Mitter/AP Photo/Red Bull)

Two F-15E Strike Eagles wait to receive fuel from a KC-135R Stratotanker during exercise Red Flag 15-1 on their way to Nellis Air Force Base, Nev., Jauary 23, 2015. The F-15s are assigned to the 4th Fighter Wing. U.S. (Photo by Airman 1st Class Aaron J. Jenne/Reuters)