A-Air Plane
W-Wind
E-Earth
(horizontally) ->
v(A,E)=v(A,W)+v(W,E)
and if the plane is stationary on the ground because of the effect of conveyor belt going the other way,
v(A,E)=0
if the plane is moving v(A,E) is not 0
(i think most of the people took earth and wind as the same thing, its not)...