Virgin Galactic has teamed up with US-based Boom Technology to develop the jet, which will be 10 per cent faster than the now defunct Concorde.
Flight times between Sydney and Los Angeles could be halved if plans for a new supersonic jet get off the ground.
The XB-1 Supersonic Demonstrator, a prototype of a larger airliner and nicknamed the Baby Boom, was unveiled at a hangar in Colorado on Wednesday by US-based Boom Technology and Richard Branson's Virgin Galactic.
The jet will be 10 per cent faster than the now defunct Concorde and two-and-a-half times faster than current jets, meaning it will be able to cut flight times dramatically.
Travellers will be able to fly between Sydney and Los Angeles in less than seven hours and for much less than the price of a ticket on Concorde, which had its first commercial flight in 1976 and became famous not only for its sky-high airfares but its famous passengers including Mick Jagger and Elizabeth Taylor.