| Answer | Crossword Clue |
|---|---|
| AIRSPACE | It's guarded by military planes |
| AIRSPACE | Area protected by military planes |
| HEAVEN | It's guarded by the Pearly Gates |
| HADES | It's guarded by the three-headed dog Cerberus |
| paravanes | A device towed behind a boat at a depth regulated by its vanes or planes, so that the cable to which it is attached can cut the moorings of submerged mines |
| frustums | The portion of a cone or pyramid that remains after its upper part has been cut off by a plane parallel to its base, or that is intercepted between two such planes |
