This is only an issue for one of my games so far. It said there was an update, so I refreshed the game. Now every time I send a squadron to attack, patrol, or another airport they disappear the moment I deselect them. However, they are still there, as I can see when they arrive at the airport and on a patrol I can see the patrol circle, just not the plane. I would attach images of the visual glitch but "an unknown error" keeps occurring.