The design is a lot like a hang glider likely using kerosene as the fuel for the 4 rocket type engines on it.
Back in the late 60s someone came up with a backpack helicopter
setup with a fold our prop that sprayed peroxide out of the nozzles on the tips of the blades to see the assembly spin. That lifted the person on the idea of a jet pack. Popular Science and later Omni Science magazines had articles on it and it could dropped down to someone stranded to see them fly out.
YouTube has a more recent version of it using a different fuel with a stand.