If you take a liquid and spill it over a surface the liquid will take the paths of least resistance. The liquid will flow until it builds up then it will spill in other areas. Air will try to spill around all the edges of a wing if held static, as air is pushed over the wing less air is spilled by the leading edge. Flowing air now spills off the trailing and wingtips, the interesting thing is air can be compressed so the amount of down draft you are discussing would not be created by the main airfoil. The wake would have to be created by air spilled by the wingtips of flying structures and by the fuselages structure. I think your down drafts would cause the air platform to move foward like a watermelon seed that has been squirted out from the pressure of your thumb and forefinger coming together. Heck, gentlemen lift is a dying factor in this jet age, strap a jet engine to a brick and the directional noozles with make it fly no matter what shape of the airfoil. Some sarcasm, to think upon!!!!

will