> They can’t hold enough fuel for more than eight minutes of flight – and even that’s the upper end. Kerosene is heavy, burns quickly, and a human can only carry so much. A battery would be far better, but they’re much heavier – at least for now. Someday someone might invent a battery light and energy-efficient enough to do better than kerosene, but, for now, you can only use what you can carry, and that’s not much.

Seems there are good enough reasons for people to not really care about jetpacks (yet). But it does seem like the military/law enforcement could have some use for it, mainly for boarding moving vehicles and/or scaling walls/barriers.