Which airspace has unusual hazards but does not prohibit aircraft flight entirely?

Restricted Areas are designated airspace regions that contain unusual hazards to aircraft, such as military operations or other activities that may pose risks. While flight through these areas is not entirely prohibited, it is heavily regulated. Pilots may be allowed to enter restricted areas, but they must do so with permission from Air Traffic Control or after confirming that the area is not active. This ensures that pilots can exercise caution and avoid dangerous situations while still maintaining the option to fly through if it is safe to do so.

In other classifications, such as prohibited areas, flight is entirely forbidden without special permission, which means pilots cannot enter at all for safety reasons. Controlled areas require specific navigation and communication protocols, but they do not inherently suggest hazards as restricted areas do. Designated fly zones are generally more permissive and do not imply the same level of potential danger. Thus, the nature of restricted areas aligns perfectly with the definition of having unusual hazards while not prohibiting aircraft flight completely.