Ok, so I went out and bought a 1080 to see how KTTF runs on the gpu. I made this airport for the next gen simulation hardware. It will run just fine on my 680 with mid level range settings in x plane, with the 1080 we usually want to boost the slider all the way right but since there are 100's and 100'd of custom objects and very dense trees it takes a big hit with full right sliders. I got my best run with AA 2 sliders down from what you have now and reflections all the way left. Try that and let me know If it improves. You will need to restart x plane after you change these settings.