Wanda and Tim have built a model airplane together 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, at least until 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 cannot fly) to go rescue them.