I spent hours making a full runway, complete with masks, blended edges, tire marks. I even got it placed perfectly in FSX. Now the bad news. I noticed the texture flickering and after some research, it seems I need to be tweaking some .asm files. It also seems that fsx gamepack doesn't even support asm files. So am I pretty much screwed with fsx gamepack?

Define "full runway". If it's all one piece, then welcome to FSX's round earth and flickering textures. If it's made of many pieces, then it sounds as if you haven't adjusted things to fit FSX's round earth to avoid flickering textures.Older modeling techniques used the FS2002 SDKs, where modifying ASM files was an included step in the process.

Hi,You need to make sure that the vertices are maximum 100 meters apart from each other. So this means that you will have to slice the polygons of your runway into pieces.From a distance you might still get some flickering, that can probably be fixed with a LOD (I am still experimenting with this).