"standing still relative to the surrounding air"

Another example...a plane that is sitting on the ground with its brakes on and its prop going flat out at full power will not generate any potential lift (upward force). It will generate plenty of potential thrust (forward force).

If a heavy wind comes at the front of the plane, THAT will generate some lift, even if the engine is shut off, because it will be passing over the airfoil...and that produces lift.

This is why a plane that's diving with its engine shut down and its prop feathered (not moving at all) can STILL generate lift from the dive, and can make a shortlived climb with that generated lift when it pulls out of the dive. Seagulls do that with absolute ease.