Comment by roelschroeven

You are correct in that the deflected airflow exerts an upward force on the wing (or at least a force with an upward component; there's also a backward component (called induced drag if my memory serves me well)).

The way the airflow exerts that force is through pressure differentials: air under the wing having higher pressure than the air above it.

Momentum change can describe physical interactions, and it's often easier to calculate things that way, but actual physical forces still exist, and can also be used to describe the same physical interactions.