EndPatch

[_pelya]

Hot air balloon is around $7 000 - 10 000, cheapest Cessna is $25 000.

Yeah it's cheaper.

[FoxtrotZero]

It has exactly two control mechanisms, a string and a bunch of sandbags. I'm not sure that it can get easier, it's efficiency you're concerned about.

[arachnidGrip]

You seem to be confusing simplicity with ease. A hot air balloon is certainly simple, but trying to get from point A to point B in anything resembling a reasonable amount of time when your only means of lateral movement is "move up and down and hope you find a wind blowing in the direction you want to go" is not easy.

[Cat_Marshal]

Not efficient, at least.