Re: STAR TREK INTO DARKNESS - Grading & Discussion [SPOILERS]
I would point to TMP as evidence that rank doesn't matter when captaining a starship. Admiral Kirk wore captain's stripes when he took over command of the Enterprise.
IIRC, if an Admiral has command of a ship, they are still referred to as Admiral. Kirk actually demoted himself in rank. That's the difference. He expected to KEEP command of the Enterprise
"Pitching is simple -- cheese for the kitchen and a yakker for the kudo." - Dennis Eckersley