Which situation is described as "prohibited" in relation to aircraft operations?

The situation described as "prohibited" in relation to aircraft operations refers to instances when flight is not permitted without specific permission from the using agency. This means that there are restrictions in place that prevent aircraft from entering certain airspace unless a formal request for approval is granted. Such conditions typically arise in scenarios involving military operations, sensitive areas, or temporary flight restrictions where safety and security are paramount.

This designation is crucial for maintaining order and safety within the airspace, as it helps manage aircraft movements in areas where unauthorized access could pose risks. Agencies use this classification to ensure that only authorized flights take place, thereby safeguarding national security and public safety.

In contrast, situations involving construction, unfavorable weather, and national emergencies do not inherently restrict flights in the same way. Although they may impose limitations or advisories on flight operations, they do not constitute an official prohibition that requires explicit permission to operate.