When I was with the Pale Riders we used to fly formations V, Abreast, Box etc. as opposed to the conga lines typically seen in game. Was a ton of fun and gave us something to do on long flights. We got to be really REALLY good at it tot he point where people would comment on how cool it looked
Getting into formation is easy. Staying in tight formation from base to target while making various turns and course adjustments is another thing entirely.
The trick is in the flight leader communicating everything from speed, to RPMs to ROC to notifying in advance exactly what he was going to do before he did it.
The trick for the rest of the pilots is to line up the guy next to you so that he maintains the same spot and distance in your view.
Takes practice and people who tend to fly together alot to get it right each time every time. But once you have it down. Its a blast