[petre]

It depends where it booms. If it's at 10 km above and nobody hears it, or above international waters, it doesn't matter too much.

[nix23]

For sure you hear it above 10km, it just does no destroy a window.

> Supersonic operations over land must be conducted above 30,000 feet or, when below 30,000 feet, in specially designated areas approved by Headquarters United States Air Force, Washington, D.C., and the Federal Aviation Administration.

https://www.af.mil/About-Us/Fact-Sheets/Display/Article/1045...

and

https://aviation.stackexchange.com/questions/17661/can-a-son...