So I decided that the model I posted below will be my final idea. I am still working on it and I have made some changes on it and I still need to make many more changes. I tested it the other day and it runs more than 5 meters, the only problem was that it didn't go straight. I'll try to have a video out soon. Even though my car's a long way from being finished and running smoothly, it's getting there.
My question for my peers is...
Does anyone know where to find some decent balloons?
I discovered that after a certain time a balloon has been used, the elasticity doesn't work as well as it did in the beginning and so, the air is being pushed out slower than the first time it was used.
Thanks and good luck