Jetpacks may get all the hype, but they’re basically just the motorized skateboards of the sky. Instead of wondering where our jetpacks are, tell us what your personal jetpack — the future invention ...

Instead of using flames and jet propulsion, as jetpacks are known to do, Raymond Li’s invention uses water to fling you up into the air. His patent hasn’t (as far as we know) been constructed yet. But ...