Cut out the wing outline from the paper you printed in the last step. Trace onto the grocery bag. Flip, and trace the other half of the wing. Trace a second wing the same way. Carefully cut out both wings. Cut a rectangle out at the middle of the straight edge of each wing piece. This allows the mechanics to move freely. Super glue the wings to the wing spars, starting at the center. Cut the right wing down the middle.
Insert the left wing into the left wing bearing. Insert the right wing and make sure that the wings can move freely. You might have to add a bit of ink tube as a spacer. When you have them moving well, remove the right wing. Glue the left wing to the the "spine" of the body. Add the right wing and just tape the centerline of the wing flaps to the left wing.