[Boveosteors]

Vacuum inside the balloon would create even more lift than helium because it is lighter (no mass?), but then there is no pressure inside the balloon to support the balloon structure against air pressure and the balloon would crush. It would require stronger and heavier balloon material to keep the vacuum and then air pressure wouldn't be high enough against the balloon to win the gravity force.

I don't exactly understand why air pressure focus to create force the way that the balloon raise (opposite direction from the gravity) and not just float more or less randomly in the air even without wind? Does gravity force gas to behave that way when gas pressure suddenly increases?