What is "restricted airspace"?

"Restricted airspace" refers to airspace where access is limited or controlled and requires special permission for entry. This type of airspace is established for various reasons, such as ensuring the safety of military operations, protecting the privacy of certain areas, or conducting specific flight activities that may pose a risk to other air traffic. Pilots must be aware of these restrictions and obtain the necessary clearances from the appropriate authorities before flying in these zones, as entering without permission could lead to serious safety hazards or regulatory penalties.

In contrast, the other options refer to different aspects of airspace that do not align with the specific definition of restricted airspace. Agricultural areas are not classified under airspace regulations but rather land use designations. Airspace lacking air traffic control is a different category altogether, typically related to uncontrolled or Class G airspace. Similarly, restrictions regarding night flights pertain to specific regulations rather than the broader definition of restricted airspace.