Re: Raises an interesting question
Helium: Maybe for a small drone, but the cubic metre of helium:kg of lift ratio puts that out of reach for anything above <10kg.
Think of the average weather balloon's size: maybe 2metre + wide to slowly lift maybe 1kg of payload? Then think of the huge balloons used by Kittinger and Baumgartner and imagine trying to compress even some of that into a cylinder small and light enough to not shrink your payload capacity enough to make the whole endeavour pointless.
Lifting balloons' lifting effect is also too "slow" for this "need lots of lift NOW" use, else Baumgartner wouldn't have taken 2.5 hrs to reach 38km - 253metres/minute or 4m/sec with a realllyyyy slow initial acceleration.
A basic airbag solution could maybe work for non-human payloads, but deceleration trauma of 120mph to zero in around 4 feet would really mess a human up.
Maybe rocket assisted braking like Curiosity, but I wouldn't want to be the poor sod on the ground set alight under the rockets!!