"air walls" = insulated concrete forms made of styrofoam encasements currently have an R-50 insulation factor and can withstand a 400 MPH wind!
Standard concrete block or insulated wood frame walls have an R-8 insulation factor.
It might not be pure air, but styrofoam is as close as we got so far.
http://www.icfweb.com/
Was that what they meant by air walls? I guess they made a good prediction about that.