Wanda and Tim have built a model airplane for a model show. Ms. Frizzle decides to shrink the class so they can fly in it. Tim, Phoebe, and Liz stay on the ground to operate the remote control, but then it gets smashed. The class learns all about flight. Meanwhile, Tim, Phoebe, and Liz try to turn the bus into different airplanes (two of which can't fly) to go rescue them.