RE: are we interested in air speed or ground speed ? Does it matter
When a car or fast motorbike passes you at high speed, you notice that. .!!!!
The bonus of ground speed is the downwind leg is percieved to be faster with aircraft.
As you watch and fly your plane as it zooms past yourself the ground speed is very relevant.
These gizmo that measure speed are airspeed so guess you just add wind speed on for ground speed.
Are doppler checkers airspeed only?