I didn't glue them to allow for easier transport. They are held in on the leading edge by the wood tabs on each wing. Then by the bolts on the trailing edge.

Also, I just got some advice about reversing the one elevator servo. There are a few vids on youtube about reversing the servo internally. Not to hard if you can solder well. However, it seems my servos have the motor mounted directly to the circuit board. Not as easy as swapping two wires on the motor. I will say the plane flies fine the way I currently have the elevator set up.