Gravity Industries in the UK have a working jet pack, although flight time is extremely limited, I think in the order 5-10 minutes, and it isn’t designed to fly at altitude. The founder demonstrated using it for rapid casualty assistance in mountains recently, although I’m dubious about the actual usefulness given the difficulty in actually controlling the thing - it’s more like a paramedic would end up smeared across the mountain themselves than actually assist a casualty in anything but the calmest weather.

https://m.youtube.com/watch?v=gtvCnZqZnxc