The Pioneer Team, a civil aerobatic team from Italy, let off pyrotechnics from their Pioneer 330 aircraft during the Malta International Airshow off SmartCity Malta, outside Valletta, Malta, September 24, 2016. (Photo by Darrin Zammit Lupi/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)

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

A hot air-balloon flies during the International Lorraine Mondial Air Balloons Festival, in Chambley-Bussieres, eastern France, Friday, July 26, 2013. (Photo by Mathieu Cugnot/AP Photo)

A view of balloon depicting an Alebrije, is seen at the 14th Solar Balloon Festival in Envidago December 31, 2014. According to the festival organizers, the Alebrije balloon will be largest replica of an Alebrije. This year features a theme on Mexican history and culture, organizers added. (Photo by Fredy Builes/Reuters)

Crew members work to secure a hot-air balloon after landing at the city of Luxor, south of Cairo, Egypt December 13, 2016. (Photo by Amr Abdallah Dalsh/Reuters)

Handout grab taken from YouTube of Commander Chris Hadfield who has said goodbye to life on the International Space Station by making a cover version of David Bowie's Space Oddity. Issue date: Monday May 13, 2013. (Photo by Commander Chris Hadfield/YouTube/PA Wire)