Are you referring to where AI airplanes park to ? If yes, GSX has exactly *zero* effects on them, no matter what you do in GSX, AI will park according to completely separate rules, which GSX has no control over.
Yes, you can set airline parking codes in a GSX profile, but they are used ONLY by GSX and ONLY for one thing:
- To supply extra scoring in the selection of the handling operators you choose from GSX. Note that, this functionality has been basically rendered obsolete by the ability to select individual multiple operators on each parking spots. Again, this refers to the handling/catering operators that you call from GSX using the GSX menu and service your airplane only. Nothing to do with AI.
- Another reason to set airline parking codes in GSX, is that when you land on an airport, IF your plane livery has matching codes to the ones had set in a GSX airport profile, you will initially see the GSX menu suggesting ONLY parking spots for "your airline", with an option to un-filter the view, and see all parking spots.
Those are the one and only places where having parking codes in GSX matters.