Richard Lugg is a Maine neighbor of mine who has a company called HyperMach that is working on hyper-sonic jet engines for aviation and aerospace applications.
To cover that retreat, the company trumpeted its Sonic Cruiser, a futuristic 250-seater jet that would fly close to the speed of sound and clip hours off long-haul flights.
Supersonic Aerospace International have been developing a 12-seater luxury aircraft, the Quiet Supersonic Transport (QSST) jet, which they hope will take to the skies in 2013 and reduce the noise of the sonic boom to no more than the noise level of a truck driving past your window.