any ideas on how to create a model airplane from wood?

Question

this monoplane will have to fly in a gym for about 4-5 min with a rubber band motor powering the propeller.
this will be made using strips of balsa wood.

Answer 1

You are going to have to go and look at monofilm (I think it is called) airplanes where the wing is a thin transparent film. Nothing made entirely of wood will be light enough to stay up for 4-5 minutes under rubberband power - even with the film you will have to have a very big slow moving propellor and properly shaped high curve wings.
http://www.indoorduration.com/
http://www.indoorduration.com/williamschapter1.htm

Answer 2

6.5 to 7.5 wingspan you should use balsa wood very light and better preformance in a plane