Holy Cow Batman! This looks fun, but I don't think I have what it takes to do it...
That looked like Upper Austria (Oberoesterreich) or Salzburg. Anybody know?
Wikipedia says modern wingsuits can achieve glide ratios of about 2.5 with vertical descents as slow as 25 mph (which means you're still going over 60 mph horizontally!)
Just found this pdf which gives some good info
http://www.flylikebrick.com/articles/flb_fallrate_vs_glideratio.pdf
FWIW, as a young boy, I tried to build a Rogollo kite (like a hang glider). Strapped it to my back, rode my bicycle down the steepest hill I could find nearby. I momentarily achieved lift, disconnected from the bike, lost all speed and crashed big time. That worked out about as well as jumping off the roof of our garage with a parachute made from a bedsheet stuffed inside a metal lunch box strapped to my back. Tales of a junior aeronautics engineer.