An RPAS (Remotely Piloted Aircraft System) is a subgroup within UAVs (Unmanned Aerial Vehicles).
RPAS differ from UAVs in that at all times there must be a pilot taking responsibility for the flight. Which means that, although the drone is flying autonomously, the pilot is continuously monitoring it and can take control at any time. In addition, the rule indicates that a pilot may not fly more than one drone at a time.
Then any remotely piloted aircraft will be a drone. Therefore, we can find drones such as aircraft, helicopters, multicopters, hybrids, or other types that can be developed. Balloons and airships are excluded.