As described on the Exploratorium website (www.exploratorium.edu/science_explorer/hoopster.html):
Cut the card into strips, about 1 X 5inches long.
Tape one piece into a loop, and another two into a larger loop (by taping them end to end first).
Tape the loops onto each end of a straw, lined up with each other.
Throw the hoopster like a spear. It will rotate and fly quite well.
Play around with variations on the basic hoopster, and compare how they fly (make sure to have several trials with each):
change the number of loops
change the orientation of the loops
change the length of the hoopster by adding straws (push one end into another)
add weight with paper clips or modelling clay
Discussions of the forces involved:
The forward motion is called thrust and is generated by our arm pushing it forward.
The air moving around the loops gives it lift so that it can fly for a while.
Air resistance eventually slows it down and gravity brings it to the ground.