A method and a device for an operating center for aiding in the preparation and management of missions of an aircraft. After a plurality of digital data has been received, the plurality of data comprising at least one datum of avionic type and one datum of open-world type, at least one flight plan is prepared from the plurality of data. The at least one prepared flight plan and the at least one datum of open-world type then are formatted. The formatted data in the form of an electronic document usable directly by a computer system of the aircraft are transmitted to the aircraft.