A system and method for protection of aircraft against surface-to-air missiles deploys sensors to provide coverage around an airport. The use of a fixed (or slow moving) set of sensors (10) around the airport allows detection of missile threats (28) to all aircraft (26) using the airport without requiring each individual aircraft (26) to be provided with a threat detection system. Information about a detected threat (28) is then typically transmitted in real time directly to the aircraft (26) under threat to allow timely deployment of aircraft-based countermeasures (30). The detection system and method preferably employ spaced-apart sensors (10) with overlapping fields of view to provide enhanced tracking through triangulation and reduced false alarm rates by redundancy of information. Airborne systems with overlapping coverage may be also used.