G2 & 3 also have a free download page where you can go & download planes that other users have created.

However, I think OMP's offer of a free 15 day trial is very generous. I have G2 because I got it for free, but I liked what I've seen of Aero Fly Pro Deluxe, I think it is called. I would certainly take OMP up on their offer. Who knows maybe they'll even give ya a break on the price since it is a legitimate school project with limited funs, hint hint good PR for OMP!