What are the forces involved with flight?

What might you see from the air?

paper airplane instructions

Ken Blackburn's Guiness Book of World Record's site at http://www.paperplane.org/ (Time aloft was 27.6 sec.) and he has a page with more links here: http://paperplane.org/links.html

Twenty five different styles of plane to make: Paper Airoplane design
10 paper airoplane designs with animated folding instructions: Learn how to make 10 great paper planes
Best paper airoplanes
One example of a 'plane' with few variables, other than size and mass, is the 'Bishop's Hat Flyer'. It is made out of an isosceles triangle of paper, with the 'base' folded over a few times to create a band, which is then curved around to form a circle (by slotting the two ends of the band into each other). You have a shape like a bishop's miter, which you don't throw, but drop. I could make a video to show how to make it, and how it works, but it's really easy and doesn't require a student to have especially good folding/fine-motor skills to make, nor do they need to have good throwing skills, as the aerodynamic design causes it to gain thrust as it falls, rather than the thrust being generated by the throw. This site has some instructions: http://www.ase.org.uk/practicalprimaryscience/exp_prim_08.html if you are interested.
Overview of the scientific method from Science Buddies: http://www.sciencebuddies.org/mentoring/project_scientific_method.shtml