Gee, to my unlearned brain it sounds an awful lot like congo and Pfadfinder were saying the same thing - albeit congo's was probably the correct way of *saying* it.
One was saying "if you are travelling at a groundspeed of 100 into a headwind of 25, the air rushing over your craft is going to be read as 125"
The other was saying "if the air being read rushing past your aircraft is 125, and you're travelling into a headwind of 25, your groundspedd will be 100."
Congo's was the second, and makes more sense since all aircraft have airspeed indicators, and for the interests of energy and stalls etc that's what's important.
For traveltime though, you're more interested in groundspeed so... you know. Each to his own?
