In fact he's "the ultimate vehicle" so you don't need another. They want to keep the game uncomplicated and pure it seems. World premiere at the VGAs.
"There aren’t any playable vehicles in the game,” said Rocksteady boss Sefton Hill. "What we’ve really focused on is Batman himself. We see him as the ultimate vehicle.” There's huge expectation for the sequel from the studio, so vehicles likely scared them.
Batman: Arkham City receives its major world premiere at Spike's VGAs this December 11th, and it releases on Xbox 360, PS3 and PC in fall 2011.