A method and system that prevents engagement with neutral aircraft utilizes secondary surveillance radar (SSR) in conjunction with traffic alert collision avoidance systems (TCAS) conventionally found on various commercial aircraft. The system and method provide for detecting interrogating signals sent out by a TCAS system of an interrogating aircraft searching for another aircraft that may pose a threat for collision. The system and method of the invention provide for a base system generating signals responsive to the interrogation signals such that there is a decreasing time difference between the interrogating signals and the responsive signals. The decreasing time difference indicates to the interrogating aircraft that another aircraft is approaching its airspace urging the neutral aircraft to change course and avoid entering a guarded tactical airspace thus avoiding unnecessary engagement of the aircraft.