CaptainCargo
I apologise if I misunderstood the motivation for your post. I did not interpret it from your original message. If your point is that this is an aspect of science that is both difficult and generally poorly taught, I wholeheartedly agree.
Before you start the campaign to strike out mention of Bernoulli's theorem in any elementary texts though, I would caution you to consider carefully the logic of the arguments presented.
The super little Java simulator in one of your links demonstrates very nicely that the flow pattern around an aerofoil is predictable. Once you know the flow pattern, you can calculate the lift. I'd be very surprised if the FoilSim applet does much integration of momentum fluxes in a Newtonian way -- more likely it uses Bernoulli's theorem to calculate the pressure at each surface knowing the velocity (you'll see they calculate the pressure coefficient).
The key part of the "why" that is so difficult to explain simply is "Why is the flow pattern the way it is?" The physicist's explanation is that it is calculable from the governing equations and the boundary conditions -- just do the sums.
But that's very unsatisfying for the layman, who doesn't want to be told, for example, that gravity obeys a relatively simple set of field equations if you'd just solve them for the earth and the moon, but rather prefers to be given Keppler's laws that describe the motion of the planets and satellites. So we're left with a need to give a simple explanation of why the flow pattern around a wing looks the way it looks.
The
Equal Transit Time" assertion (pleeeeeaaaaase don't call it "Bernoulli's theorem") is one little untruth designed to do just that. It gets the right result for the wrong reason.
So knowing that it's untrue, you understandably reach out for an alternative. How about "air gets deflected downwards"? That seems to be the gist of the "turning flow" argument that you want to prefer. But does that explain
why so much airflow changes direction around the wing? Before you say "yes, it's obvious", take a look at the
Skipping Stone theory, put your hand on your heart and tell me that this is not the picture at the back of your mind when you say "of course the air is deflected downwards". But as an explanation, it's just as wrong as the first one.
I have to admit defeat here. I cannot come up with a good intuitive non-circular explanation of why the air moves faster over the top of a lifting aerofoil than over the bottom, or why a huge tranche of air is deflected in its vicinity, at least not one that stands up to detailed inspection. The best I can do is along the lines of asserting that the flow must be parallel to the trailing edge, and the only allowable flow that fits the symmetry of the situation is something that circulates around the aerofoil. But that's more of a qualitative explanation of the way the maths works than an explnation in its own right. Even so, the inability to provide a simplistic explanation is not, IMHO, the same as saying that we don't
understand something. For anyone who wants to, the theory is there, and it's been perfectly well tested and proven over a hundred years of practial flight.