GEEZ it looks great. As a diorama builder must say its a great effort on your part to put this together.
I would put some yellow lead in lines for the aircraft parking positions and also maybe suggest powdered grass glued to your board for even more realism. thats only my opinion but it does look fantastic and the staining effect is not overdone by any stretch, I work airside and I know what aprons affected by wear and tear look like.
Congratulations and well done
Steve Kicic