Aircraft enthusiasts are waiting with growing anticipation for the unveiling of plans for a supersonic jet that may be able to fly London to Sydney in just four hours.
U.S. builders - helped by the Nasa space agency - will reveal the prototype successors to Concorde at the Farnborough air show next month.
Boeing, Lockheed Martin and Gulfstream are leading the way to build the new supersonic passenger plane which will be targeted at first at the business jet market.
All three companies believe they are close to reduce the sonic boom to a sound described by a Gulfstream engineer last week as 'closer to a puff or plop'.
He said: 'The fact that the big boys are all close confirms industry rumours that a new generation of supersonic planes is now, finally, within reach.