| Answer | Crossword Clue |
|---|---|
| ECHOES | They travel at the speed of sound |
| UFOS | They might travel at warp speed |
| CHUCKYEAGER | First pilot to travel faster than the speed of sound |
| do | travel at a speed of doing 55 on the turnpike |
| speeding | (of a motorist) Travel at a speed that is greater than the legal limit |
| supercritical | (of a flow of fluid) Faster than the speed at which waves travel in the fluid |
| subcritical | (of a flow of fluid) Slower than the speed at which waves travel in the fluid |
