What is a type of Special Use Airspace that restricts flight?

The correct answer involves understanding the purpose and function of different types of Special Use Airspace. A Military Operations Area (MOA) is a designated airspace where military training and maneuvers may occur. While aircraft are not prohibited from flying through an MOA, these areas allow for military operations that may be hazardous to non-participating aircraft, hence pilots are advised to avoid them or exercise extreme caution when flying through.

In contrast, Warning Areas exist over international waters and serve to warn pilots of potential hazards due to military activities. Although flights can still occur, they should be cautious.

An Alert Area indicates a high volume of pilot training or unusual aerial activity, but similarly allows access for air traffic.

A National Security Area is designated to protect the national security interests of the United States, where flight is discouraged, but unlike MOAs, entry is typically not actively restricted unless specifically prohibited. Understanding these distinctions clarifies why a Military Operations Area is recognized as a type of Special Use Airspace that restricts flight due to the potential hazards present.