In this blog post we saw that lift derives from the downward acceleration of the relative wind, which has mass. Thus for any given value of indicated (repeat indicated) airspeed, the angle of attack must be the same regardless of altitude.

This is because indicated airspeed is a direct measure of the ram air pressure -- of the rate of air mass flow over the wings. Some confirming experiments in FS will be found here.

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Now ... Proof by simulator generally doesn't count as a proof at all. However, the results do support my argument. They make the chief assertion more believable in the eyes of those who are unwilling or unable, for whatever reasons, to follow the mathematics of the proof.

So let's say that you know nothing of the lift-as-momentum assertion, and that you know only about the simulator results.

If you're willing to accept those results at face value, you would be able to DERIVE the origin of lift from the angle-of-attack-versus-indicated-airspeed results alone ... Because the mathematics of the situation again are inescapable.

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If lift is a function only of angle of attack and indicated airspeed, as the simulator results say, this can only mean that lift is a function of angle of attack and the rate of air mass flow over the wing. There are no other possiblities.

So one is then compelled to investigate the reason that lift relates to air mass flow. One is then led immediately to F=mA and the proof is trivial to complete.