I’m part of a group that flies multiplayer formation constantly. I was really disappointed to discover that multiplayer aircraft have a number of issues with visibility in MSFS.
Aircraft are only visible within about 1,000 feet, if that. Beyond that range you can only see the tag (if it’s turned on) and the tag doesn’t even show the distance to the player! Very unhelpful and very difficult to rejoin on someone as they suddenly snap into view only when you are on top of them.
Once in formation, the other aircraft begin to fade away if you get within about 25 feet of them. That is no good for the close formation we usually do.
I am really hoping that a workaround can be found (maybe similar to the small object radius fix in FSX) or put into place with a future update!