Here is a glimpse of the future. By 2050, seaweed-powered space-liners will fly from London to Tokyo in two-and-a-half hours, at a cruising altitude of 20 miles and generating no significant pollution.

This is not the speculative vision of a latter-day Jules Verne but the confident prediction of the Airbus parent company, EADS, which will unveil its plans for a hypersonic, stratospheric airliner, the Zehst, at the Le Bourget airshow near Paris today.

The Zehst – or "Zero emission hypersonic transportation" – will fly twice as fast and twice as high as Concorde, if joint European and Japanese development plans come to fruition.

The likely cost of a 90-minute "space flight" from Paris to New York would be €6,000 (£5,300) per passenger. The Zehst, which resembles a lightweight version of the US Space Shuttle, would carry up to 100 passengers at speeds of up to 4,800kph (3,000mph).

The aircraft would have three different forms of propulsion in order to eliminate noise problems and meet future ecological constraints. The plane would take off using quiet turbo-reactors powered by a biofuel made from seaweed or algae.

To reach its cruising height just outside the atmosphere, the Zehst would use clean rocket engines fuelled by liquid hydrogen and oxygen. Once in the stratosphere, it would switch to another form of rocket propulsion.

"This is not an aircraft and not a rocket, it's a commercial rocket plane," Jean Botti, EADS director-general for technology and innovation said yesterday. "The future of air travel will look something like the Zehst."

Boeing, the great American rival of EADS and Airbus, is also working on a new generation of supersonic airliners and has already conducted test-flights with a pilotless model.

The unveiling of the plans for the Zehst today is part of a merciless publicity and commercial war between the two aerospace giants.

EADS hopes to distract from the first trip outside Europe of Boeing's new stretched version of the Jumbo, the Boeing 747-8, which touched down at Le Bourget yesterday.