In my experience it happens when there is something obstructing not only the runway. It also happens if there is something obstructing the taxi way or if there is something obstructing the spawn points.
I explain. If you stops in the middle of runway or you crashes end the restof your plane remains in runway, the runway is blocked so IA use not to land.
If the airfield has only one exit to go to park areas, IA sometimes also does not land. Other times (i thing it depend on version) lands and then crashes with the obstacle.
If you're flying missions created by you (or other people) has to review that there are not static objects near or over spawn points. If at some moment all spawn points are occupied by objects or airplanes that have already landed, other airplanes do no land because there are no places to park ( other times they land and dissapear when arrive at the end of runway)
Finally, the problem could be that you have not reached all the waypoints of your rute. Your wingmans reach them when you reach them, so if you don't follow them your wingmans wait until you reach the landing point. So they fly around you (if not try to entry in formation with you and crashes ..) until you reach that point. Even though you are already landed, "officially" you have not reach the point because there are waypoints that you have not flyed. In the case there are 2 options.
1.- provide to your group the command "go to next waypoint" as times as next waypoint will be landing point
2.- or provide to your group the command " return to base" .
the issue here is once , the "official" next waypoint for your group is the landing point, your wingmans are going to ignore any other command from you and are going to be focused in to land only.
yes .. IA is not much Intelligent
