| Answer | Crossword Clue |
|---|---|
| SSTS | Mach-speed jets: Abbr. |
| SSTS | Mach speed jets: Abbr. |
| SSTS | Mach+ jets |
| TRANSONIC | Having Mach speed |
| ERNST | Physicist Mach who lent his name to a measure of speed |
| hypersonic | Relating to speeds of more than five times the speed of sound (Mach 5) |
| machs | MACH, a number relating the speed of a body to the speed of sound |
