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)

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

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)

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.)

A Hot air balloon is seen at the Cup Hot Air event during the Air Sports festival titled “70 Years of Peaceful Sky” in Minsk, Belarus July 18, 2015. (Photo by Vasily Fedosenko/Reuters)

Spanish Patrulla Aguila (C-101), aerobatic demonstration team of the Spanish Air Force performs during the Radom Air Show at an airport in Radom, Poland August 23, 2015. (Photo by Kacper Pempel/Reuters)

The Screamin' Sasquatch jet powered Waco Biplane sits on display during media day for the Canadian International Air Show at Billy Bishop Airport, Toronto, Ontario, September 4, 2015. (Photo by Louis Nastro/Reuters)

People leave a giant air purifier, which its inventor calls a “super tree”, in Lima's district of Jesus Maria November 24, 2014. In Peru's notoriously polluted capital Lima, local inventor Jorge Gutierrez, a retired naval engineer, is deploying the giant air purifiers that double as billboards to suck up carbon dioxide and dangerous levels of smog. (Photo by Mariana Bazo/Reuters)