Host seat coordinates are usualy away from the main action area and that is why there is nothing there.. System creates one runuway with host(server) aircraft sitting there. It does help with fps when you have tons of units and you need server computer to use every single MHz on AI allover the map.
Stop the game completely to get rid of the log.lst error.
So, if you have crated mission right (comit flights after waypoints, and you see them on scheduel flight list in upper left corner), you don't have to use host aircraft. You can take any other plane or gunner position. Just remember that when you host mission for others, you leave server online even if you die for your mission planned duration.
Some tech stuff off topic:
If you really put huge number of units and set them on the move, problems could start. When the game start to have "time overflow" (see the console), than AI units start to do strange things like warping, flying sideways, flying trough terrain etc. But on the modern computers (i7 4GHz+) you can host and fly no problem. It depends on a lot of stuff and the tehnics ini you make for the campaign. I've made million tests on that metter and i can tell you that if you have <2500 nstationaries, <30barrages, < 100 ground moves, <80 airplanes in the air, you are safe to host and fly on modern 4GHz+ machines.
If you create monsters, like me because i can not resist, than you need separate server with minimal graphics settings in the window and as fastes CPU you can have. My maximum on i7 OC to 4.7GHz was 3800 nstationaries, 50 triggers, 40barrages, 150 ground moves and 150 planes in the air. Fps on machine like that was ~40fps at the beginning of the mission when it is the most intense. It is possible to add even more, but is recommended to leave safe margin in case of sudden fps drop.
I will explain those tips and trics in my third video.
Cheers,
Thor