Hypersonic passenger plane LAPCAT A2 explainer

The Long-term Advanced Propulsion Concept and Technologies (LAPCAT) was developed by British company Reaction Engines Limited (REL) and funded by the European Space Agency (ESA). The 139-meter long hypersonic plane has four liquid hydrogen-powered Synergistic Air-Breathing Rocket Engine (SABRE) engines and can carry up to 300 passengers.
It can travel up to 6,100 kilometer per hour - five times faster than the Airbus A380. By using liquid hydrogen as fuel instead of fossil fuel it is also greener and would only produce water vapor and nitrous oxide instead of carbon emissions. SOURCE: Research and Technology Agency, Reaction Engines Limited (REL), Transport Research & Innovation Portal