For more than half a century aeronautical engineers have been working on the dream of hypersonic passenger flight.

London to Sydney in four hours is an often cited goal.

In Discovery Gareth Mitchell looks not at the past history of hypersonics, but at current developments.

He meets engineers working on the propulsion systems and developing new materials specifically for hypersonic flight.

Technologies which could be one applied to space craft as well as aeroplanes. Show less