Flying multi-ship formations of C-141's, I can tell you that fuel burn increases dramatically for the follower/wingmen due to all the throttle jockeying to keep position, You'd have to have a hell of an auto-pilot to achieve very tight spacing between aircraft to achieve the desired results. Also the amount of fatigue induced by flying formation for long periods of time is incredible, like flying a CatII approach to a moving runway for 5 or 6 hours non-stop!!!just ask those B-17 drivers of yore.