Aircraft Detectors Aircraft are suppose to fly higher than 1,200 feet and if they try to fly lower it brings suspicion upon the aircraft and the pilot.  Drones are limited to 400 feet from the ground or the top of a structure, and each businesses drone is also limited to an 5-mile radius from an airport, further for private drones.. {See FAA restrictions for variations and changes} Any person attempting to fly a drone over the BorderTransportationSystem will have the drone detected and either caught by nets, or jammed by a signal jammer, or allowed to be followed to its destination where the receivers will be apprehended by the authorities.  Index of ... Drone Detection En Route {aircraft} Operations {FAA restrictions} Unmanned Aircraft Systems (UAS) Frequently Asked Questions/Help