A drone means a no crew onboard device and intended for surveillance missions, intelligence, exploration, transportation, etc.
The size of a drone and its weight (several grams to several tons) depend on the desired capacity. The autopilot or from ground allows long flights of several tens of hours.
Drones can be used for the benefit of the armed or security forces of a state, police, customs, etc.
It uses the UCAV(Unmanned Combat Air Vehicle) term to designate a so-equipped weapons materials to military use.
Unmanned Combat Air Vehicle : This type of drone was designed to provide intelligence, combat and surveillance zone.
The CIA has developed into an armed version then also controlled by the US Air Force.
The USAF officially changed the name to « General Atomics MQ-1 Predator, » given its use of increasingly important as an armed drone. A Predator1 UCAV can pull a Hellfire missile.
The US Air Force is currently by far the world’s largest combat drones user.