An Unmanned Combat Air Vehicle (UCAV), also known as a combat drone or drone, is an Unmanned Aerial Vehicle (UAV) that is usually armed. These aircraft have no onboard human pilot. Operational drones are predominantly under real-time human control, with the human's role in UCAV system varying according to levels of autonomy of UCAV and data communication requirements.

Equipment necessary for a human pilot (such as the cockpit, armor, ejection seat, flight controls, and environmental controls for pressure and oxygen) are not needed in a UAV, resulting in a lower weight and size than a manned aircraft, which can allow for greater payloads, range and maneuverability.