An unmanned combat aerial vehicle (UCAV),[2] also known as a combat drone or drone, is an unmanned aerial vehicle (UAV) that is usually armed (aircraft ordnance), such as with missiles. Aircraft of this type have no onboard human pilot. These drones are usually under real-time human control, with "the human's role in UCAV system [varying] according to levels of autonomy of UCAV and data communication requirement[s]". 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, as the operator runs the vehicle from a remote terminal, resulting in a lower weight and size than a manned aircraft. While several nations possess and manufacture unarmed UAV, only the United States, Israel, China, Pakistan and Turkey[3] are at present known to have manufactured operational UCAV as of December 2015.