It sounds like I missed a really entertaining exchange about airspeed!!! I'm not really much interested in stirring up a hornet's nest, but I am curious about that. And I don't think I have any preconceived notions about what the right answer is.

Lets start with airplane A, flying 30 mph, IN NO WIND. His ground speed (speed relative to the ground) is 30 mph and because there is no wind, I think his airspeed should be 30 mph. Maybe it isn't I'm sure someone knows!!!

Now, same airplane, same ground speed, but wind is 10 mph on the nose. This makes the airplanes airspeed 10 mph higher, so it is airspeed is 40 mph, for the same 30 mph groundspeed. Again: maybe this is wrong, etc

Now, starship Enterprise (the real one NC 1701 not 1701A, B, etc) swoops in and teleports the plane 180 degrees the opposite direction!!! I think because of conservation of momentum the plane has to be going 30 mph relative to ground; but it's airspeed must now be (30-10) = 20.

When you turn a REAL model or REAL plane, it cannot make this instantaneous change in direction, so maybe there is a "conservation of airspeed" but this would imply a change in ground speed. Hmm, wonder if there's any way to confirm/deny that?....

Now COMPLETELY ignoring any theories etc, what I observe when I'm flying my little models (they seem to react more than the bigger ones) is that they go a certain speed into the wind (call it "50 undefined units of speed") and when I turn around, flying in the direction with the wind, they slow down to 20 or 30 UUS. Ground speed reducing. This speed is from my frame of reference, so I think that is ground speed.

I think that means that the airplane tries to maintain airspeed, with a resultant change in ground speed.

Is that right?

Regards