It's often used colloquially to mean "very fast" (see also: Sonic the Hedgehog). However, there are some major differences between supersonic and hypersonic flight. Here's what each term really means.

CONCORDE-STYLE flights capable of blasting passengers from London to New York City in 3.5 hours have edged closer to reality ...

So, an aircraft flying at supersonic speeds at an altitude of 50,000 feet will generate sonic booms for 50 miles on the ground. How loud the sound is within that area can vary.