An electronic system for controlling an unmanned aircraft, the system comprising: - a remote device for managing the flight of an aircraft, adapted to communicate remotely with the aircraft and comprising: - a remote module for acquiring flight plan data, and - a remote module for calculating a remote trajectory or setpoint according to the flight plan data acquired by the remote acquisition module; and - at least one on-board device for managing the flight of the aircraft, carried on board the aircraft, the on-board device comprising: - an on-board module for acquiring flight plan data, configured to acquire the flight plan data acquired by the remote acquisition module, and - an on-board module for calculating a remote trajectory or setpoint according to the flight plan data acquired by the on-board acquisition module; the remote device comprising a trajectory validation module configured to: - acquire the on-board trajectory or setpoint and the remote trajectory or setpoint; - validate the on-board trajectory or setpoint or reject the on-board trajectory or setpoint based on the remote trajectory or setpoint; and - transmit the result of the validation to the on-board flight management device; the on-board device comprising a generation module configured to acquire the result of the validation of the trajectory validation module and to generate steering instructions, adapted to be interpreted by an autopilot, according to the result of the validation; characterised in that the system comprise at least three on-board devices for managing the flight of an aircraft, and wherein the system is configured to select a primary on-board device to generate the flight control instructions, the selection of the primary on-board device depending on the on-board trajectory or setpoint calculated by each of the on-board devices. - a remote device for managing the flight of an aircraft, adapted to communicate remotely with the aircraft and comprising: - a remote module for acquiring flight plan data, and - a remote module for calculating a remote trajectory or setpoint according to the flight plan data acquired by the remote acquisition module; and - a remote module for acquiring flight plan data, and - a remote module for calculating a remote trajectory or setpoint according to the flight plan data acquired by the remote acquisition module; and - at least one on-board device for managing the flight of the aircraft, carried on board the aircraft, the on-board device comprising: - an on-board module for acquiring flight plan data, configured to acquire the flight plan data acquired by the remote acquisition module, and - an on-board module for calculating a remote trajectory or setpoint according to the flight plan data acquired by the on-board acquisition module; - an on-board module for acquiring flight plan data, configured to acquire the flight plan data acquired by the remote acquisition module, and - an on-board module for calculating a remote trajectory or setpoint according to the flight plan data acquired by the on-board acquisition module; the remote device comprising a trajectory validation module configured to: - acquire the on-board trajectory or setpoint and the remote trajectory or setpoint; - validate the on-board trajectory or setpoint or reject the on-board trajectory or setpoint based on the remote trajectory or setpoint; and - transmit the result of the validation to the on-board flight management device; - acquire the on-board trajectory or setpoint and the remote trajectory or setpoint; - validate the on-board trajectory or setpoint or reject the on-board trajectory or setpoint based on the remote trajectory or setpoint; and - transmit the result of the validation to the on-board flight management device; the on-board device comprising a generation module configured to acquire the result of the validation of the trajectory validation module and to generate steering instructions, adapted to be interpreted by an autopilot, according to the result of the validation; characterised in that the system comprise at least three on-board devices for managing the flight of an aircraft, and wherein the system is configured to select a primary on-board device to generate the flight control instructions, the selection of the primary on-board device depending on the on-board trajectory or setpoint calculated by each of the on-board devices.