You can cut out the polygons of the wings and use them for ailerons.

But that is just one way to skin a cat.

For me, I would prefer to cut out the polygons and delete the separate parts. I would then cap the open space by creating several polygons to cove the parameter of the aileron area. Then I would create a separate aileron with a box or cylinder and link that aileron to the wing.

I know it's a complex move just to make a simple aileron, but that's how I did it when I started my never-finished aircraft project [Project Have Blue]. I feel sorry for letting that project down, especially after all the effort I put into modeling the shape and learning to export.