A highly safe drone is provided. A remote controller and a drone are connected to each other through a network and cooperate to operate. The drone includes a flight control unit, a flight start command reception unit receiving a flight start command from a user, a drone determination unit determining a configuration of the drone itself, an external environment determination unit determining an external environment of the drone. The drone system has a plurality of states including a takeoff diagnosis state and satisfies a condition transitioning to another state. The takeoff diagnosis state includes a drone determination state where the drone determination unit determines the configuration of the drone itself and an external environment determination state where the external environment determination unit determines the external environment. The drone system makes the drone to takeoff after transitioning to the takeoff diagnosis state upon receiving the flight start command.