I confess I have not read each post here and indeed the subject has been looked at from a variety of angles. However with fear of prolonging an already lengthy post, here is my two cents..

Indeed the airplane is traveling in an airmass and knows not whether it travels upwind, downwind or crosswind. Gusts, sheer, turbulence aside of course.
The issue which must concern us is what is described as"Illusions Created by Drift". This is simply theillusion of increased or decreased airspeed and also of skidding or slipping during turns when turning from upwind to downwind or vice versa. This illusion results from taking visual cues from outside the aircraft, rather than the flight instruments. In full sized aircraft this condition is at its most noticable when flying low and in high winds. It is taught to develope recognition and avoidance of the possible repurcussions.
In RC aircraft we observe the aircraft from outside at all times and are subject to the same illusions, if not even more so. It seems important to manage airspeed and attitude with this in mind.

Now on the subject of aviations great questions....

If a 747 has a cargo of chickens which weighs 20,000 pounds, and should those chickens all a once start to fly around in the cargo hold, does the aircraft weigh 20000 pounds less.

pjp01