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 is 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.
EADS, which has been working on Zehst with the Japanese for five years, is obviously keen to put down its old rival.
"I've heard nothing to suggest that Boeing's hypersonic plane would be environmentally clean like ours," Mr Botti told the newspaper Le Parisien.
"I don't think we are behind them. They are certainly going to have a surprise."
- INDEPENDENT