This instructable will teach you how to build a simple glider. I will also attempt to show the results of a slightly more elaborate build for a biplane and a helicopter.
Step 1: The Materials
1. Cardboard (I used a pizza box because my son is 2 and has small fingers. For performance the thinner cardboard of a cereal box would work better)
2. A writing utensil (Sharpie for me, please)
3. A cutting implement (I used scissors because my son wanted to help. An exacto knife would have given cleaner results)
4. A keyring ring (a paper clip would also work)
That was all that was necessary to make the basic glider. The slightly more advanced, and I use the term lightly, builds of the helicopters and the biplane also required the following.
6. Hot Glue Gun
7. Hot Glue Sticks
Step 2: The Design
Step 3: Cut Out and Assembly
Step 4: Final Thoughts on the Glider
Step 5: The It Rest of the Cardboard Air Force
Essentially, the design step was the same. I drew a design on the cardboard and then I cut it out. On the second helicopter and the biplane I ended up cutting the fuselages 3 times and then sandwiching them together with hot glue for more strength. The first helicopter just saw me going back and re-enforcing key sections (the tail, the rotor pivot point, and the skids with additional cardboard and hot glue.
To make the rotors and the propeller I stuck a toothpick into the fuselage at the pivot point for the moving blades. It was hot glued into place and then a small cardboard square was impaled on it and glued into place. This was essentially to make it so the blades had more of a contact point with the fuselage for added support and since I hot glued from below to ensure no glue would get on the rotors and cause them to stick. Next I hot glued 2 long, thin pieces of cardboard into a cross formation. This was then impaled on the toothpick as close to the the center point as possible. Another tiny square of cardboard was impaled on the toothpick over the rotor blades. The toothpick was then cut down to stick out just above the last cardboard square. And finally I finished this off by putting a glob of hot glue on the end of toothpick. This was for safety reasons. The result was a firmly fixed toothpick pole with a pair of rotor blades that could be freely rotated by hand.
And with that method I was able to create a helicopter and a biplane that are durable enough to be played with and cheap and easy enough to make that if my toddler should break them it's no loss at all. The final cost on this build came up to a whopping $0 since I already had everything I needed. These took a little more work than the original glider but still it was only about 20 minutes for each one.
My final thought on these is that the next time we need to add aircraft to our air force I will let my son color or paint these (after I draw the fuselage but before I cut them out) so he can be a little more involved.