The X-1 could break the sound barrier in level flight. That is to say, it could move across geography, in a measurable way, faster than the speed of sound. Cr

The X-1 could break the sound barrier in level flight. That is to say, it could move across geography, in a measurable way, faster than the speed of sound. Creating a sonic boom in a deep and dangerous dive is an interesting quirk in a fighter, but it doesn’t set new speed records that would interest the general population.