I've known test pilots who have flown supersonic routes over continental USA at high altitude and had zero complaints. The boom intensity depends on weather con

I've known test pilots who have flown supersonic routes over continental USA at high altitude and had zero complaints. The boom intensity depends on weather conditions. Other times they did get complaints because the boom sounded like gunshots and got reported to the police. Cruising above 60000 ft the boom from a larger aircraft might be noticed but not be objectionably loud.