Final answer:
Military Flying Areas within High Level Airspace are designated with specific identifiers like Military Operations Areas (MOAs) in the United States and are outlined on aviation charts, although designations can vary by country.
Step-by-step explanation:
If a Military Flying Area is within High Level Airspace, it is usually designated with a specific identifier depending on the country's regulations. In the United States, for example, such areas are typically identified as Military Operations Areas (MOAs) and are meant for military flight activities, such as training or maneuvering at high speeds that can be hazardous to non-participating aircraft. However, these designations can vary by country, and in some cases, they are also referred to as Restricted or Prohibited Areas when the intent is to completely restrict entrance by non-authorized aircraft.
Most often, these military areas are outlined on aviation charts, which pilots must consult to ensure they are aware of any restrictions or required communications procedures. When not active, civilian aircraft can often transit through MOAs without restriction, but it is crucial for pilots to check the status of these areas before flight to ensure safety and compliance with regulations.