Which of the following categories must be included when requesting to fly in controlled airspace?

The request to fly in controlled airspace typically requires the inclusion of the aircraft category and registration number because this information is crucial for air traffic control (ATC) to identify the aircraft and ensure safe separation from other traffic. The category defines the type of aircraft, which can affect its operational limitations and handling characteristics, while the registration number uniquely identifies the specific aircraft in question.

This information allows ATC to ascertain the appropriate rules and procedures that apply to that aircraft type and to provide any necessary instructions or interventions safely. Proper identification is vital for maintaining situational awareness and ensuring the efficiency of airspace management. Other elements, while important in different contexts, do not directly relate to the fundamental requirements of flying in controlled airspace.