They actually used to have a single electric cart on the long walk from the garage to the terminal building when they were building the TWA building and moved yellow cab pickup to the NYCTA Bus area (partway to terminal closer to garage). Maybe that is what is left on the website, you know the excellent web services provided by B6 are.

I haven't seen it in ages. Even when it was there it usually was parked by the elevators on the terminal side with no one around.