Hello everyone.
I'm sorry for late answer but I just found this topic accidentally.
The reason of such a big aircraft.cfg file (I'm talking about PMDG's 737 series) is actually caused by my mistake.
During a painting a new repaints I've added ONE line into description and used it as a template for any new project. However, I wasn't aware that if I do not close this line, it will copy itself one by one. Insane but true. I have already received a feedback from many pilots about this matter and this is something what I'm going to fix for each plane from 800WL and 900WL version. From info what I have it happen only with this planes. All others - 600,700 and 777-200/300 - don't have this problem.
I'm sorry that this things happened to you, it was not my intention to mess up with this files. :/
Like I said, I'm going to fix all planes where this problem occur. It is going to take a while since I will have to edit and recompile all repaints.
One more thing - some people found that this big files have something to do with performance. Some other (including me) not. But I think it's a matter of individual spec like it has a place with fsx.cfg tweaking. :/
Best Regards,
Wizzardos