What does "Fast" refer to in terms of target speed?

In aviation and military terminology, the term "Fast" often refers specifically to aircraft or targets that are traveling at higher speeds. The range of 600-900 knots ground speed is typically classified as "Fast" because it encompasses the operational speed of high-performance aircraft and some military operations. This speed range is critical in various contexts, such as intercepting or engaging with enemy aircraft, where understanding the speed classification is vital for tactical planning and execution.

The selection of this specific range is relevant for understanding target dynamics within air operations, as targets moving at these speeds present unique challenges and requirements for detection and engagement. Understanding this classification helps operators quickly assess situations and apply appropriate strategies when encountering targets.

The classification of speeds below or above this range helps delineate different operational behaviors of aircraft, allowing for better mission planning and execution under varying conditions.