User blog comment:Sokatsui/Young Justice Techonology/@comment-1038387-20121025094833/@comment-5165918-20121025111740

We have hydro-jetpacks. But not jet-jetpacks. Hydro-jetpacks, as in the name, use water. You put the tail in the water, it's sucked it, and the water pressure blasts you a few feet above the water.