The Zero Emission High Speed Transport or ZEHST is a supersonic passenger airliner project by EADS. EADS revealed the proposal at the Le Bourget air show (June 18, 2011). It is expected to fly at mach 4, 32km above the ground, and it will carry 50 to 100 people. It will combine three propulsion systems: two turbofans for take-off and up to Mach 0.8, then rocket boosters up to Mach 2.5, then two underwing ramjets would accelerate it to Mach 4.
EADS has estimated it would cost well in excess of €15 billion ($22 billion) to bring the design to market. This would be distributed across a fleet of 50 to 100 aircraft. Mr. van Toor says the company had not put a price on a ticket yet, but he adds: “We would imagine the cost of the ticket to be much more than the premium fare of today’s aircraft. It will be for the lucky few.”