In this Wednesday, July 13, 2016, handout image provided by Solar Impulse, the Solar Impulse 2 flying over the pyramids, Egypt Cairo. The experimental solar-powered airplane has arrived in Egypt as part of its global voyage. (Photo by Jean Revillard, Rezo via the AP Photo)

Željava Air Base, situated on the border between Croatia and Bosnia and Herzegovina under Plješevica Mountain, near the city of Bihać, Bosnia, was the largest underground airport and military air base in the former Yugoslavia, and one of the largest in Europe. (Photo by Thomas Windisch/Exclusivepix Media)

A passenger plane, with a full Harvest moon seen behind, makes its final landing approach towards Heathrow Airport in London, Britain, October 5, 2017. (Photo by Toby Melville/Reuters)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

Actors perform in a scene during the “Dino Safari” show in Tokyo, Japan, 25 April 2018. The Dino Safari show features dinosaurs moving in a realistic way thanks to the Dino-Tronics mechanism that enable the dinosaurs to walk, move their heads and jaws. The event will run from 26 April to 05 May 2018. (Photo by Franck Robichon/EPA/EFE)

Amy Rimmer, Research Engineer at Jaguar Land Rover, demonstrates the car manufacturer's Advanced Highway Assist in a Range Rover, which drives the vehicle, overtakes and can detect vehicles in the blind spot, during the first demonstrations of the UK Autodrive Project at HORIBA MIRA Proving Ground in Nuneaton, Warwickshire on Friday October 21, 2016. (Photo by Fabio De Paola/PA Wire)

A man photographs the main engines of the space shuttle orbiter Discovery on display at the Udvar-Hazy Smithsonian National Air and Space Annex Museum in Chantilly, Virginia August 28, 2015. Shuttle Discovery had 27 years of service and flew 39 times before being retired in 2011. (Photo by Gary Cameron/Reuters)

A handout image provided by the New Zealand Defence Force shows aid supplies being unloaded by Fijian soldiers from an Royal New Zealand Airforce C-130 Hercules plane in Suva, Fiji, 23 February 2016. Tool kits, generators, ration packs, water containers and chainsaws make up part of the New Zealand relief following Tropical Cyclone Winston. The death toll from the cyclone that hit Fiji over the weekend climbed to 29, local media reported ON 23 February. Cyclone Winston, the most powerful storm in Fiji's history, battered the country's main island of Viti Levu and other smaller surrounding islands on Saturday, the Fiji Broadcasting Corporation reported. (Photo by Sam Shepherd/EPA/NZ Defence Force)