exclusion zone 
noun
An area into which entry is forbidden, especially by ships or aircraft of particular nationalities: aircraft had violated the air exclusion zone...
- A two-mile exclusion zone for shipping and aircraft was set up around it.
- The crack RAF team was forced to call off its acrobatics because the aircraft violated an eight-mile exclusion zone needed for the performance.
- There will also be an air exclusion zone over central London and police helicopters will relay aerial pictures to the control room.