Media Platforms Design Team(Credit: All Photos by Reaction Engines) British firm Reaction Engines is building a plane that can zip almost anywhere in the world within four hours, cool itself by 1000 degrees Celsius in a fraction of a second, and even go into space. The European Space Agency is interested in the futuristic plane as a way to lower the cost of future launches.The Most Bizarre Planes Ever MadeMedia Platforms Design TeamReaction calls the aircraft the Skylon, and it imagines the plane carrying 300 passengers at mach 5. It’s powered by SABRE, which sounds like a villainous spy organization but actually stands for Synergetic Air-Breathing Rocket Engine. Those engines could be cooled to -160 degrees Celsius using compressed helium. The $1.1 billion plane would be 276 feet long—40 feet longer than a Boeing 747.Armed with liquid oxygen engines, the Skylon could even enter Earth orbit; ceramic composites would prevent damage from re-entry. The plane could be hitting runways in just five years, making for some of the most fascinating passenger voyages possible.Media Platforms Design TeamMedia Platforms Design TeamMedia Platforms Design TeamVia Policy Mic.John WenzWriterJohn Wenz is a Popular Mechanics writer and space obsessive based in Philadelphia. He tweets @johnwenz.