A prototype battery-powered plane, called Greased Lightning or GL-10 is pictured flying at NASA's Langley Research Center in this undated handout photo obtained by Reuters May 1, 2015. The plane, which has 10 engines and can take off like a helicopter and fly efficiently like an aircraft, is currently in the design and testing phase. (Photo by Reuters/NASA)

Star Wars actors on the Cantina set at Star Wars Celebration: The Ultimate Fan Experience held at the Anaheim Convention Center on Thursday, April 16, 2015, in Anaheim, Calif. (Photo by Richard Shotwell/Invision/AP Photo)

High-wire artist Kane Petersen successfully walks a tightrope 300 metres above the ground at Eureka Skydeck on September 16, 2015 in Melbourne, Australia. The walk was the highest tightrope walk ever attempted in the Southern Hemisphere. The stunt is to mark the arrival of the film “The Walk” to Australian cinemas in October. The stunt saw Kane mimic the film's French high-wire artist Philippe Petit, who successfully walked between the twin towers of the World Trade Center in 1974. (Photo by Scott Barbour/Getty Images)

A dancer lets a Russian tourist practice the traditional tannoura dance at a cafe in the Red Sea resort of Sharm el-Sheikh, Egypt November 10, 2015. The fallout from the crash of a Russian Metrojet passenger plane in Egypt's Sinai Peninsula could slash tourism income from Sharm al-Sheikh by half, the head of the region's travel agents' association said on Tuesday. Several airlines have suspended flights to the Red Sea resort since the Oct. 31 crash, which investigators and Western governments believe was likely to have been caused by a bomb. Thousands of Russian and British tourists have been flown home. (Photo by Asmaa Waguih/Reuters)

A hot air balloon in the likeness of Yoda from Star Wars prepares for liftoff at the 21st Philippine International Hot Air Balloon Festival at the former Clark US Air Force base in Pampanga Province, Philippines on February 9, 2017. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

PETA (People for the Ethical Treatment of Animals) activists wear crocodile masks during a demonstration against the use of crocodile skins ahead of Milan's Fashion Week, in Milan's Duomo Square, Italy, Tuesday, February 21, 2017. Milan Fashion Week opens Wednesday. (Photo by Antonio Calanni/AP Photo)

Yaroslav Segeda at the top of a high rise building in Kudrinskaya Square, Moscow, Russia. (Photo by Yaroslav Segeda/Caters News)

Collided passenger train cars are seen in Taebaek, South Korea, Tuesday, July 22, 2014. Two passenger trains collided head-on in eastern South Korea on Tuesday afternoon, killing one passenger and injuring dozens, fire officials said. (Photo by AFP Photo/Yonhap)