It's been more than ten years since Concorde made its final transatlantic flight.

But there's a new generation of supersonic passenger aircraft beginning to emerge, boasting speeds at least twice as fast as current commercial planes.

While these planes will first appear in the private and business jet market, catering only to the super rich with gargantuan price tags and first class service, supersonic may eventually reach regular holidaymakers.

One such jet, the N+2, designed by US global aerospace Lockheed Martin, is intended for commercial airlines, and aims to cut the travel time from New York to Los Angeles by half - from five hours to just 2.5.

The aircraft would accommodate 80 passengers and have a tri-jet configuration in which one engine is on top of the aircraft and the other two are under each wing to reduce sonic boom.

'To achieve revolutionary reductions in supersonic transportation airport noise, a totally new kind of propulsion system is being developed,' said Michael Buonanno, Lockheed Martin manager of the NASA N+2 program.