Originally Posted by Johnny Footstool
You have to assume Bruce Wayne had significant stashes of cash, passports, and vehicles in various locations throughout the world, and that he had a network of tunnels to allow him to get into Gotham without being noticed (that is, unless he wanted to put on a public display like he did earlier in the movie).
You're the first person that I've asked that hasn't said "because he's Batman."
This actually makes some sense. Just hard to believe considering he had to ask Alfred if they still had any cars around earlier in the movie.