Hrmmmph!

No! I'm not referring to the ones NASA
experimented with in earth-orbit in
the 1980's. I'm referring to the type
invented in 1961, using hydrogen- peroxide reacting with a silver catalyst
for generating exhaust-gas [H20^ + O2^], for "down-to-earth" purposes.

I remember seeing one of those on TV used by a stuntman during the opening ceremonies for the 1984 Summer Olympics
in Los Angeles.
Problem with those type of jet backpacks was [and is] they only
provided useful thrust for something
like 30-40seconds...Hardly practical.

NOW!...I've recently seen something
on TV that can change that pessimistic
picture: Lightweight [kevlar/carbon-fiber] super-strong compressed-air storage-tanks that can hold air/gas at upto and over 10,000psi [640 atmospheres].
Those kevlar/carbon-fiber storage tanks with hundreds of cubic-feet of volume are incredibly light. Anyone of
you could lift them without much effort.

So I did some number-crunching.
And two backpack-cylinders made of such material, each cylinder 30 inches-long,
6-inches in diameter, containing air at
10,000psi, would combined hold just over 50Ibs of compressed-air.
And, theoretically, all that compressed-air could generate an "average" of over 660Ibs[3,000N] of thrust for 600 seconds, unlike the 30-40 seconds of thrust for that jet backpack
invented in 1961.
Imagine! You could have a [Buck Rogers/Jetsons] backpack propelling
you to terrific speeds for upto ten minutes!
I don't know the initial thrust/drag ratio, but I guess an average speed of
60mph wouldn't be out of the question.
In ten minutes, you'll cover six miles.
Are we onto something or not?

Jacob