If Batman has some kind of fabric that is light, some kind of skeleton that mimics the bat's bones that hold its wings open, I don't see why it couldn't potentially be of service.
As I mentioned, having the cape floating & freely designed, it doesn't really make a difference as reduction of terminal velocity is concerned... So, if he could have the skeleton, it could do some parachute's work....
Thanks for your insightful comments, you're appreciated!