"If the sky was full of cars flying all over the place, it would affect the skyline. And it would be noisier and there would be a greater probability of something falling on your head. Those are not good things," says Elon Musk.
As any GSCE science student knows, all that sound is wasted energy, an unnecessary by-product of the engine's true purpose which is to push the car forward. Does it really matter what a car sounds like?