In elementary school I remember hearing the planets move in CIRCLES in THE SAME PLANE around the Sun.

In an atom, electrons would also move around the nucleus like a mini-solar system.

For seven and eight years old children, it's a fair simplification, I guess.

Ocean waves work like this: water molecules are piled up in humps, and all the molecules slide across the ocean, while the water underneath the humps does not move. If you poured some dye into the waves, the water-humps would carry it along.

Sound works like this: vibrating objects put energy into air molecules, then the molecules zoom all the way to your ears at the speed of sound. They put the sound vibrations into your eardrum. Then they zoom all the way back to the vibrating object. Then repeat.

Uh, that's all wrong. Not oversimplified. Just wrong. (Airfoil explanations are similarly wrong. Not just oversimplified.)