I like Gorilla Glue for joining wings. Wet the socket in the wing halves and paint a light coat of Gorilla on the dihedral brace/wing joiner. The Gorilla glue foams up to fill all the space. You do have to tape the wing halves together and check every 30 minutes or so and wipe the excess glue foam off. It will push the wing halves apart if the socket isn't tight. I have never seen one of these fail. I have seen failed epoxy joints where the glue was only stuck on one side due to a loose socket.

Buy a small bottle of Gorilla and after you use it, squeeze all the air out and replace the cap. It lasts longer this way.