This paper airplane flaps its wings when thrown.
I found the design here. Yesterday, I messed up my first attempt at making it, but this afternoon Cole and Owen and I succeeded.
It works—it's best to throw it in a quiet place so that you can enjoy the soft sound of the flapping—something like the sound of several pigeons taking off from a ledge, high above you.
The design calls for a penny to be taped into the bulgy part at the bottom. The airplane hardly veers off to the side at all when it's thrown—Cole and I were practically playing catch with it.