Enterprise always was longest, and they made it longer. (same time they completely redid the superstructure). Enterprise is the fastest, partly due to its length. (length=sleekness for a ship).
I consider the JFK fully Kitty Hawk class. (if the JFK isn't Kitty Hawk, then the Bush isn't Nimitz) Enterprise is her own class, but clearly "Kitty Hawk esque". (kind of like Ticonderoga vs Spruance)