Zero Emission Hyper Sonic Transport

The Zero Emission Hyper Sonic Transport or ZEHST is a planned hypersonic passenger jet airliner project by the multinational aerospace conglomerate EADS and the Japanese national space agency JAXA. On 18 June 2011, the ZEHST concept was unveiled by EADS at the Le Bourget Air Show. The envisioned vehicle uses a combination of three different types of engines, including relatively conventional turbofans, rocket motors, and scramjets to attain a maximum speed of Mach 4.5 (four and a half times the speed of sound).

Source: Wikipedia — Zero Emission Hyper Sonic Transport (CC BY-SA 4.0)