Yes, you understand my plan. The solid body inside the wing is deleted. Only the air is kept for meshing.

Your plan is to keep the solid body inside the wing and delete the air.

Having a watertight set of surfaces is one way to create a filled solid wing. You haven't shown how well an adjacent skin matches at the common edge between the patches. Once you cover the entire wing surface and the side openings in patches, it will automatically become a solid unless the edges don't match.

The other way to make a filled solid wing is to start with a solid block and cut the wing shape into it using Split Body, either keeping the air or the filled wing as I demonstrated in the skin tool video.

The size of the mismatches in the edges of adjacent skin patches should be smaller than the the smallest cell height of the air mesh on the skin. Have you already calculated the height of the first cell?