Off the coast of Pusan, South Korea: An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) breaks the sound barrier in the skies over the Pacific Ocean. VFA-151 is deployed aboard USS Constellation (CVN 64). This is an edited version (reduced grain). (Photo credit: Wikipedia)
This is an amazing clip showing audio and visual demonstrations of supersonic flight, with a clear and concise explanation.