I saw this idea in the Family Fun magazine and since my son love to fly paper airplanes, I knew we had to try it out. It really was pretty easy and provided lots of fun for us. Here are the steps.
Gather your supplies: 2 same size plastic cups, 2 rubber bands, tape, drawing of a rocket cut out (my son drew one, colored it and cut it out).
Cut four slits on the top of one of the cups equal distances apart, about 1 inch or so. Cut the rubber bands in half. Attach the rubber bands to the slits and tie a knot on the end to secure it and then tape the rubber band to the cup. The two rubber bands should form an X. Tape the rocket to the cup with the rubber bands.
Place the cup with the rocket on top of the other cup. Push down and then let go! Take turns sailing it into the air to see how high it can go.