I reported this before and was told to get tracks.  Well, it happened again and I got three of them and they do show the plane as invisible.  It just happened that I was flying with the person, 12.OIAE_Snake9, and as as result we were able to test a little.  We were on the Syndicate server.  He had no idea his aircraft (Pe-2) was invisible until I told him, everything looked normal from his side.  The most interesting thing was that once he fired his guns he became visible.  All three tracks are