Helium balloon wi-fi


An article in New Scientist about using blimps for mobile phone repeaters got me thinking: would the same thing work on a smaller scale? Hang a wi-fi antenna from a small helium balloon. Easy way to get line-of-sight without having to climb trees, roofs, etc.

Major problem would be stopping the balloon from leaking. Are there small balloons that stay in the air for more than a few days?