Wrong. Momentum change is momentum. The time rate of momentum
change is Force. Neither is pressure.

What I wrote (or intended to write) is that pressure is manifested by
many momentum changes. Each molecule that collides with a wall
transfers momentum to that wall, and the net force caused by all those
momentum changes (over time) manifests itself as pressure, (which is
force divided by area). The essential point is that pressure arises
from momentum transfer on a molecular level.

Why does Newton require that air be accelerated downwards?

To counterbalance the wing being accelerated upwards due to lift. The
wing is at an AOA which generates lift.

If we let the system
stabilize, the air molecules will pile up near the earth, and be sparser
further up.

What color is the sky on your planet?

Blue. Why? Do you not concur with the observation that on Earth the
air is denser near the ground, and less dense at higher altitudes?

Gravity is what holds the earth's atmosphere in place.

Jose
--
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