Abstract: A flight management system of an unmanned aircraft linked to a control station by communication means includes: a first set of a number N of successive navigation functions (iND with i=1, . . . N) remotely situated within the control station, a control function on board the aircraft, generating, from guidance setpoints, commands intended to control the aircraft so that it observes the guidance setpoints, and a second set of a number N of successive navigation functions (iNE, with i=1, . . . , N) on board the aircraft, and configuration means, capable of performing a combination of a number N of successive functions, each of the successive functions being chosen from the first and second sets, said combination of successive functions generating the guidance setpoints transmitted to the onboard control function.