When flying on course into a headwind, what is true about groundspeed?

When flying into a headwind, the key concept revolves around the relationship between groundspeed and airspeed. Airspeed is the speed of the aircraft relative to the surrounding air, while groundspeed is the speed of the aircraft over the ground.

In the case of a headwind, which is a wind that pushes against the airplane as it moves forward, the resulting effect is a reduction in the groundspeed compared to the airspeed. This is because the headwind effectively subtracts from the forward speed achieved by the aircraft's engines. Therefore, if an aircraft has an airspeed of 100 knots and encounters a 20-knot headwind, its groundspeed would be 80 knots. This demonstrates that when flying into a headwind, groundspeed will always be less than the airspeed.

Understanding this relationship is crucial for pilots, as it affects flight planning, fuel consumption calculations, and estimated time to reach a destination.