| Answer | Crossword Clue |
|---|---|
| FLYZONE | Restricted airspace |
| NOFLY | -- zone (restricted airspace) |
| RADAR | Airspace monitor |
| RADAR | Airspace monitoring device |
| FAA | U.S. airspace monitor |
| NORAD | US-Canadian airspace protector: acron. |
| airspaces | AIRSPACE, the portion of atmosphere above a certain land area |
| birdcage | the airspace over an airport, together with the airplanes in it |
