Here is a design for a small, pocket-sized plane made from a post-it note. It is easy to make and flys suprisingly well. This is my entry for the pocket-Sized Contest
Step 1: Get a Post-It note.
Get a post-it note. The ones with the sticky strip on them are best, others will work, though. Peel of one note, and lay it down sticky side up on a table.
Step 2: Fold the sticky strip
Fold the sticky strip over, letting it stick to the rest of the note.
Step 3: It starts to become a plane...
Fold the paper in half, unfold it. Fold down the upper corners. Make sure the sticky strip is in the front.
Step 4: Fold in sides
Fold in the sides of the plane, there should be two points at the back of the plane. (Look at the pics.) Fold in half again.
Step 5: Fold out wings, and finish up
Fold down the wings, I like to make them even with the bottom of the plane. Re-crease all the joints to make the plane stronger.
Step 6: Put it in your pocket
Fold the wings down, so the whole plane is flat. Slide it in your pocket.