Final answer:
Sonic booms are produced by aircraft traveling faster than sound, causing shock waves that result in two booms heard when the aircraft passes. These can cause damage and are why supersonic flights over populated US areas are not allowed.
Step-by-step explanation:
An aircraft can create sonic booms when it travels at speeds faster than the speed of sound, which are generated by the shock waves that form at the nose and tail of the aircraft. As these shock waves propagate to the ground, they are perceived as two separate booms, corresponding to the time it takes for the aircraft to fly past a stationary observer. Notably, during space shuttle landings, these dual booms were frequently heard by viewers.
Due to the high pressures generated by sonic booms, which can cause damage such as breaking windows, supersonic flights are prohibited over populated areas in the United States.