Why wouldn't the Concorde travel lower than the stratosphere?

The Concorde did not travel lower than the stratosphere primarily due to the need to avoid excessive air resistance and turbulence that occur in the denser air of the lower atmosphere. Operating at higher altitudes, typically around 60,000 feet, allowed the aircraft to achieve optimal speed and fuel efficiency while minimizing drag. Additionally, flying at stratospheric levels helped reduce noise pollution over populated areas, as the sonic boom created by supersonic travel was less disruptive at higher altitudes.