I remembered this old(?) topic and had to register, because few days ago I got this idea to overlay runways with skidmarks. Here is a screenshot of what I got (the texture is bad, but you should get the idea).http://users.tkk.fi/~lapelto2/fgfs/fgfs-skidmarks.jpg
(edit: the image was a bit too big, so here's the link instead)
It works by shifting the texture coordinates of the runway and then using an effect to overlay the skidmarks image. I used my blender importer&exporter to do the work, so that's why there is some gaps and errors. But the image spawns across multiple runway elements.
So + sides would be: Possible to have multiple different skid marks. Few or many, long or short etc.
and -: Needs modifications to genapt & rebuilding of the airports, might lose texture precision (but I don't think so). And needs the shader effect (without it the runway looks like it used to do).