It's a combination of ridge lift and gliding down the hill from the top. You can actually fly all the way from the very top of the hill out to the flats at the bottom with no wind. At the end of the day as the wind is dying, usually Wayne is at the top doing 10 loops in 5mph just to get the last 5 feet to the top then he'll fly off with almost no wind and when he lands his kite falls down without a puff of wind. The last scene in this video is exactly that.
http://vimeo.com/18835141 You'll see everyone standing around with out a lick of wind while he fly's over us. It's soooo fun!