The 5-minute process is mute, as you can fly for 6 miles in that time. however, it is very impratical; a better option for a jetpack would likely be solar power with the backup being a much better-developed energy source; It is said that energy can't be destroyed, only transformed. so if we could transform it back then we could havee limitless energy. I don't believe that sort of thing will happen for a while.