zooman, I think that you said that you went to Borneo? There is an entire "flying" fauna there in the Dipterocarp forests of gliding frogs, snakes, lizards, and the "flying lemurs".
Here's a cool website on flying snakes: Flying Snake Home Page
Here's video footage of a Draco lizard "flying": Flying Snakes... and Leaping Lizards - YouTube
The other side of this question is whether these flying lizards are the inspiration for dragons.
In Borneo perhaps. But in China the image is very old. In Europe it is quite old. Did these cultures know of Borneo's flying lizards that long ago? I doubt it.