 We have seen the car that went faster than the speed of sound. But the speed of sound was more than just a milestone. Early experiences with aircraft traveling near the speed of sound caused so many problems, crashes, and deaths that the speed of sound came to be considered a barrier, the sound barrier. One of the most famous incidents was the breakup of the DeHavillian Swallow and death of its pilot, Joffrey DeHavillian, Jr. in 1946. Structural failure occurred as the air built up, pitching the aircraft into a shock stall that placed tremendous loads on the fuselage and wings. The main spar cracked at the roots, causing the wings to collapse. Here's how the sonic boom works. As an object travels through a fluid, like air, it creates waves that encircle it. As the object approaches the speed of sound, these waves get bunched up at the front of the vehicle, creating a shock front that places all sorts of stress on the aircraft. At the point that the speed of sound is exceeded, the shape of the cone gets narrower. The sonic boom is along the front edge of the cone and follows the aircraft. Observers on the ground will hear one boom. That boom will travel with the jet.