The Bell X-1 Jet Looks Like a Bullet—And It’s Not a Coincidence

Thinking a little outside the box and considering things that do travel fast and design isn't an obstacle such as a bullet vs traditional aircraft design and the problems with high speeds on safety, control and the airframe itself leads to innovations. I hadn't actually thought much about where the term sound barrier came from but that makes a lot of sense based on what Your posting had to say on the subject. When you now see mach 1 and even up to mach 3 in aircraft its amazing how coming to grips with the principles mentioned here made that possible.