I have always tried to explain my views on the realism issue like this. Batman's gadgets, vehicles etc are and always will be a stretch of the imagination. However, in Nolan's films he presented these fictitious elements in such a way that they could be precieved as more something that could actually exist. Tried to design them with a semi-military feel etc. Design aside, they were able to give an explaination as to where they came from, what their original purpose was, and so on. The tumbler was originally an armored vehicle meant to jump distances to tow cables and build bridges. Hence the jet exhaust. He dresses up as a bat to freighted his enemies, but things like his ears have microphones to hear from a long distance or a blue tooth type thing to talk to Alfred or Fox. I'm not saying they ARE real, simply that they made the possibility much more convincing and functional so to speak, opposed to previous batmobiles or batwings that you could see had little to no function or realism. Now, even though the "Bat" in TDKR was supposed to be for urban terrain, I will admit, for the realism feel, that one was a bit over the top since it kind of went against physics.