Jammers can be installed in the airports to disrupt the control on all major frequencies used in remote controlled models, but you can still program a drone to fly to a preset GPS waypoint autonomously. As a r/c model enthusiast, i dont see a solution to this problem. If one wanted, he could build a drone capable of seriously damaging an a/c fly it right into a landing a/c, and he would only need a month or a couple months of setup and training so the fact that this hasnt happened yet is just due to terrorists being lazy and narrow-minded.