Here's a toy one, good reviews, but fragile (have tape) and prob use once - https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Balloon/dp/B00LW7WGRK http

Here's a toy one, good reviews, but fragile (have tape) and prob use once - https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Balloon/dp/B00LW7WGRK https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Ball... Practically perhaps you could use the principal to manage buoyancy on lighter than air... unlikely though, to much added complexity.