Originally Posted by
Planespotta
Of course you can. It will only be legal, though, above FL600.
EDIT: This is what I've learned from the FARs, so it's probably different for military flyers in MOAs and other restricted areas.
In US airspace, > M1.0 is flat-out illegal at any altitude...the underlying reason is noise abatement. Several manufacturers are exploring super-sonic biz jets which will be designed to spread the shock wave out so as to not generate a sonic boom (more like a "sonic rumble"). However, the law doesn't clearly allow for "quiet" supersonic flight, so they will have to get the law changed before they are in business.
The military is exempt of course, although they go to great lengths to minimize sonic booms in poulated areas.
There is no technical reason that prevents supersonic flight at sea-level, it just takes more power and structural strength, and aerodynamic design features...many fighters can do it. It's easier at high altitudes due to lower drag and the fact that the speed of sound decreases as altitude increases.