An Unmanned Combat Air System (UCAS) refers to a type of military aircraft that operates without a human pilot on board. These systems are designed to perform various combat missions, including surveillance, reconnaissance, and air-to-ground strikes. UCAS can be remotely controlled by operators or can operate autonomously using advanced artificial intelligence. UCAS technology enhances military capabilities by allowing for missions in high-risk environments without endangering human lives. Examples of UCAS include the MQ-9 Reaper and the Northrop Grumman X-47B. These systems are increasingly integrated into modern warfare strategies, providing flexibility and efficiency in combat operations.