would this not be considered a drone? drones are not legal in national parks. can only imagine each state following suit for state parks.

Guess we have to get rid of the props and just tether it to the pack like a balloon.

Seriously though, I've often wondered if a weather balloon style lifter tethered to a backpack could help it be lighter. Probably with a less flammable gas, and only in sparsely forested areas.

Less flammable would be Helium. It just so happens that the US is looking to sell the strategic helium reserve. So you just need to find a VC and you can get your backpacker's assistant idea off the ground. hehe

as far as helium balloon, it would have to be a balloon of such enormous size to be of any benefit. To launch a couple pounds of payload to 90k feet required a balloon 8' in diameter on the ground.

A kilogram of lift per cubic meter of helium. At sea level; if you let it expand it only goes bigger at altitude, without needing more helium.

Great, so if I have a 25kg sack, a 1 meter sphere being trailed above is only going to make it 24kg. Like I originally stated, a few pounds required an 8' diameter balloon, so 2.5m balloon. That's friggin huge. FYI, at 90k' altitude, the balloon expanded to about 40' before reaching it's burst limit allowing for a return of the payload.

Lots of fun on windy days!