Hypersonic travel - at more than five times the speed of sound - is a dream that's existed since the second world war.
Now, fuelled by US military interest in the capacity to strike anywhere in the world within two hours, it could become a reality.
But with the grounding of Concorde last year spelling the end for Supersonic air travel, could hypersonic flight for civilians get off the ground?
Imagine it: California to Tokyo in two hours instead of twelve. It seems like science fiction, but the dream of routine hypersonic flight - that's travel at over Mach 5, five times the speed of sound - is being nurtured now.
Anxious to replace the ageing Shuttle, NASA is researching hypersonics. The X43-C is a research vehicle that'll fly in 2007 to test the revolutionary aircraft shapes and jet engines needed for such high speeds. NASA has already built - and flown - an earlier version - the X43-A.
The theory had been to boost the plane to Mach 7 on the tip of a rocket because hypersonic engines don't work at subsonic speeds. Once separated from its booster, the engine was to be switched on.
All started well, but hypersonic flight is an immense technological challenge. They'll try again later this year.
Last November, America's military chiefs awarded the first contracts for Project Falcon - worth $4.5m.
It's aim - a hypersonic missile by 2010; a hypersonic bomber by 2025, able to deliver a 12,000lb payload anywhere in two hours.
The man driving the project is a former astronaut, Ron Sega.
The physics of flight at such high speeds means hypersonic planes look nothing like today's aircraft.
Just like Concorde, they generate a shock wave in the air. So the solutions being tested in the US Air Force's giant wind tunnels have strangely beautiful arrow head shapes.
It's called a waverider: to all intents and purposes, it surfs on its own shock wave. Making them go this fast means new engines too.
Built by the University of Queensland and the Qinetiq team from Farnborough, HyShot was fired on a rocket to the edge of space then switched on as it fell back to Earth.
Scramjets have no need for all the turbines and blades of a conventional jet: they're little more than shaped metal tubes, the engine swallows enough air to burn its fuel because it's going so fast. Mind you, that is a bit like trying to light a match in a hurricane.
At Farnborough, birthplace of the jet engine, there is a model of the air intake for a hypersonic engine. It's part of a project to design an experimental hypersonic missile that can cruise at six times the speed of sound. It's called SHYFE.
High speed means high temperatures - very high. If Concorde went hypersonic, the plane would melt. It means making a hypersonic plane from special materials: composites.
The shapes, moulded from carbon or ceramic fibre mats then fired in a furnace to bake in the special temperature-resistant compounds.
And all this cutting edge materials science is going on in what's really just a cottage industry: just three small firms in the US can do this.
In a way, it seems odd that hypersonics is being revitalised now. After all, in 2003, Concorde flew for the last time; the Columbia tragedy has set back the US space programme; even the celebration of the centenary of flight never got off the ground.
If hypersonics has a future it's only because the military can afford it, what then for future passenger flight?
Well, imagine a world where all this - planes and runways - are redundant. Replaced by affordable, individually-owned PAV's. Personal airborne vehicles, in the jargon. In effect, cars, with wings. And NASA is working on it now.
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