> What exactly about this is possible? http://www.lowtechmagazine.com/2007/06/green-slow-air.html http://www.lowtechmagazine.com/2007/06/green-slow-air.html L

> What exactly about this is possible? http://www.lowtechmagazine.com/2007/06/green-slow-air.html http://www.lowtechmagazine.com/2007/06/green-slow-air.html Long-term, helium looks to have issues though, especially if we slow down natural gas mining. Perhaps we could find a tenable balance between helium and hot air. https://en.wikipedia.org/wiki/Thermal_airship https://en.wikipedia.org/wiki/Thermal_airship