Without revealing too much, what is you plane like? Is it extreme or conservative?
When I was in highschool I always drew stuff on the back of my assignments so when the teacher came by I'd just turn it over and they'd never know.
I got a CAD program for free online, but there are bug in it and it kinda sucks. I have old AutoCAD files of other plane ideas, but I worry a bit about people stealing them, not that you guys would, I'm just cautious.
Actually, for this, I used MSpaint - it's a bitmap program usually included with Windows 95/98/2000, just look under your accessories folder.
Even Apple Machintosh's Kid Pix could do the same.
Unless this link still wont work, go to my site to see more:
The meaning of life is curiosity; we were put on this planet to explore opportunities.