Developed by Swiss startup Destinus, the hydrogen-powered passenger jet prototype has been undergoing testing for the last couple of years. At the end of 2022 in Munich, second prototype Eiger completed a successful test flight. The aircraft is capable of travelling at Mach 5 and above - five times the speed of sound. The legendary Concorde operated at Mach 1 speed. The hypersonic aircraft would use hydrogen-fuelled air-breathing turbojet engines for takeoff and landing with a separate ramjet rocket engine to take it to hypersonic speeds. The startup claims the jet - essentially half rocket, half plane - would be net zero carbon, only emitting heat and water vapour. The company recently received its share of two grants worth €27m from the Spanish Ministry of Science. The first grant (€12m) will help fund the development of a hydrogen engine test facility near Madrid, which will house the startup's prototype aircraft. The second (€15m) will fund research into liquid hydrogen-powered propulsion systems. To make travelling from London to New York in under two hours possible, the aircraft would need to fly at altitudes of over 31 miles or 163,680 feet. The company's first aircraft, which could fit approximately 25 passengers, is expected to be ready by 2030.