Years ago before GPS, when we only had two VORs, we were westbound against an extraordinarily strong headwind in a Cherokee, talking to St. Louis Approach. Through breaks in the clouds I could see that the big trucks on the Interstate below were making better time than we were. It was obvious we weren’t going to make our original destination. So we were looking at our charts, and trying to calculate a good location for a fuel stop with our usual one-hour reserve. I asked Approach if they had a ground speed on us.
St. Louis Approach responded, “Sure. Do you want it in one digit or two?”