Mazda Motor introduces the company's concept vehicle, Taiki during the press day of the 40th Tokyo Motor Show at Makuhari Messe, on October 24, 2007 in Chiba Prefecture, Japan. (Photo by Koichi Kamoshida/Getty Images)

“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)

“A small British company with a dream of building a re-usable space plane has won an important endorsement from the European Space Agency (ESA) after completing key tests on its novel engine technology. Reaction Engines Ltd believes its Sabre engine, which would operate like a jet engine in the atmosphere and a rocket in space, could displace rockets for space access and transform air travel by bringing any destination on Earth to no more than four hours away”. – Chris Wickham via Reuters. Photo: Artist's impression of Skylon. (Photo by Reaction Engines Ltd)

A volunteer operates a remote controlled disinfection robot to disinfect a residental area amid the COVID-19 coronavirus outbreak in Wuhan in China's central Hubei province on March 16, 2020. China tightened quarantine measures for international arrivals on March 16 as the country worries about a rise in imported cases of the deadly coronavirus and anger rages online at how Europe and the United States are handling the pandemic. (Photo by AFP Photo/China Stringer Network)

A Filipino woman wears a mask to try and protect against the spread of coronavirus in Malate district, Manila City on March 24, 2020. The Philippines has taken drastic measures to combat the spread of Covid-19. The entire country is under strict quarantine and the army is on the streets to monitor compliance. According to official figures, there are 462 positive cases and 33 dead in the Philippines, but it is thought that thousands of cases remain undetected due to lack of resources in a country where millions of people have no access to health care. In the poorest and most crowded areas, it’s almost impossible to adhere to the physical distancing required during quarantine. (Photo by Alejandro Ernesto/The Guardian)

Richard Coleby of Polaris falls over his quad into muddy waters during day one of the HydroGarden Weston Beach Race on October 14, 2017 in Weston-Super-Mare, England. (Photo by Michael Steele/Getty Images)

A man and a dog bathe in a fountain during celebrations of Paratroopers' Day in Moscow' s Gorky Park on August 2, 2017. Russia' s Airborne Troops (Blue Berets) celebrate their professional holiday on the Day of Elijah the Prophet, their Patron. (Photo by Stanislav Krasilnikov/TASS)