Plain English Meaning
Flying the aircraft at the speed it needs to be at right now, and keeping it there steadily.
Full Definition
The skill of holding the aircraft at the airspeed required for the current phase of flight or maneuver, and adjusting it smoothly and accurately when conditions or the maneuver demand a change.
Context Anchor
You will hear this in flight instruction when an instructor is evaluating how well a student maintains the correct speed during maneuvers, approaches, and landings.
Derivation
Proper comes from a Latin word meaning “one’s own” or “suitable.” In this phrase, it means the speed that is suitable for the situation, not just any speed that seems close.
Why Pilots Care
Failure to proper airspeed can result in , excessive sink rates, or , directly affecting and .