||This article does not cite any sources. (December 2009)
A defensive aids system (DAS) is a military aircraft system which defends it from attack by surface-to-air missiles, air-to-air missiles and guided anti-aircraft artillery. A DAS typically comprises chaff, flares, and electronic countermeasures combined with radar warning receivers to detect threats. On some modern aircraft (Lockheed Martin F-35 Lightning II), the entire system is integrated and computer-controlled, allowing an aircraft to autonomously detect, classify and act in an optimal manner against a potential threat to its safety.