We have some helicopter blades. By attaching a balloon we can get our helicopter to fly. This took a little practice though. We even tried holding the helicopter upside down. Ms. Lally was our champion helicopter launcher!
We have a car that is powered by balloons. We had to figure out which way to point the balloon so that the car would move forward. We guessed correctly. This is what happens when the balloon faces one way, then the other!