Here is the helicopter we made. We added a single paper clip to the bottom, but the addition of a second or a larger paper clip might affect the flight pattern. Hmm, now doesn't that sounds like an interesting experiment!
We also played with spinning blimp toys. Here is the video from which I learned to make the blimp. How you let go of it makes all the difference in how it flies. It is a quick and easy toy to make. Ours were much thicker and made from card stock.
~Let me know how your experiments turn out.