A walkalong glider is a type of model plane that’s kept aloft, theoretically indefinitely, by someone walking along with it as it flies, generating rising air using a piece of cardboard, paddle, or even your body. Smithsonian Air & Space posted a template and instructions for making a simple paper walkalong glider. The plans come from a recent book by Stephen Voltz and Fritz Grobe (better known as the Mentos and Diet Coke guys) titled “How to Build a Hovercraft: Air Cannons, Magnetic Motors, and 25 Other Amazing DIY Science Projects.“