Originally Posted by BMatthews
Movies of aircraft flying in close proximity to clouds further supports this idea that the plane's lift is a product of interaction with the air alone. A plane has to be darn close to a cloud to produce a disturbance in the formation. By the time it's two to three wingspans away there's no effect. So again it shows that the airmass itself is able to deal with the needs for flying the plane without the need to connect with the earth.
Now that we've revised our theory to reflect the fact that the downward "push" exerted by the plane on the earth need not involve downward momentum (i.e. it's no problem if the downward momentum is damped out in just a few wingspans), your cloud observation is not a problem. Again, imagine if we are flying in honey-- due to shear forces, the honey would transmit the downward "push" of the wing all the way to the ground (or all the way to the edge of the container) even if the actual downward momentum of the honey dampened out to near zero in just a very short distance.