While this treat is almost 6 months old, I have to admit I do have the same problem over FTX UK. Elstree is a pain in the a$#. FPS are very low at this airport. I have no idea why just this small airport has so much impact on the fps while others don't. Southampton has great fps with much more AI traffic. Maybe there is a bug in the scenry causing this, but I was not able to locate the problem.