For a fast-maneuvering military aircraft, which code should be assigned?

Assigning a code of 4000 for a fast-maneuvering military aircraft is correct because this specific code is designated for VFR (Visual Flight Rules) military aircraft operating in the airspace. This option is used primarily for military operations and allows for the identification of the aircraft on radar by Air Traffic Control (ATC) while also indicating their unique operational status.

The use of a code like 4000 enables controllers to handle military aircraft differently than civilian ones, accounting for their maneuverability and operational flexibility in the airspace. This designation ensures that ATC can promptly recognize potential high-speed and agile movements characteristic of military operations and facilitate safer airspace management for both civilian and military entities.

In contrast, codes such as 1200 are typically used for VFR civilian flights, while 7700 is an emergency squawk indicating distress, and 7600 is used to signify loss of communication. These codes serve different purposes and are not appropriate for fast-maneuvering military aircraft, which require specific identification for effective coordination within controlled airspace.