From memory, it states that you can't Flat Out move if you load OR unload.
So not just dropping off, but picking up also.
Apart from that, I've been thinking of ways to get squads to VP locations with a couple of Serpents within two or three turns - what sort of distance apart, manging the ranges and so on.
Same in reverse, two Serpents and squads of Banshees, Dire Avengers and whatever else lined up to move to the Front.