Imagine a VERY LONG wing passing through the air and look at the motion of
the air near the center. Symmetry tells me that at least near the center
of the wing the air flow should be independent of which plane perpendicular
to the wing you pick; i.e., a 2D model should still work. If it would need
a 3D analysis then ends of the wing would have to give almost all of the
lift; ALL planes would have short stubby wings.