Groundspeed
What is groundspeed?
Groundspeed is the aircraft's speed relative to the ground—how fast it is actually moving across the earth's surface, as opposed to airspeed, which is speed relative to the air. It is affected by wind: a headwind decreases groundspeed while a tailwind increases it, even when airspeed stays the same. Think of it as your true "miles-covered-per-hour" for figuring out arrival times and fuel burn.
Also known as: GS, ground speed
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