Top-down view. A drone flies to the right with an airspeed of 40 kilometres per hour, its speed through the air (blue arrow). A 15 kilometre per hour headwind (red arrow and red streaks of moving air) blows against it. Adding the two gives the groundspeed, its speed over the ground (green arrow): 40 minus 15 is 25 kilometres per hour, so the drone covers less ground in the same time. With a tailwind the groundspeed is greater than the airspeed. With a crosswind the drone drifts: its track over the ground is not where its nose points. Example values from the lesson, vectors to scale, scene not to scale.
