Very nice! My kid built something like that about ten years ago for a science fair to test balsa wood wing designs. Straightening airflow is easily one of the hardest things to do. Pulling air out rather than pushing it in is a great way to do that!
This is definitely going on the "things I'll do if I ever get locked up in a room full of office supplies"-list which now carries one entry :D
nice project!
Would be great with a follow-up on paper airplane improvements discovered using the wind tunnel.