A method for manufacturing, layer-upon-layer, an integral composite aeronautical structure, wherein the method comprises: (a) providing an additive manufacturing tool comprising a depositing mold shaping an aerodynamic surface and at least one head configured to be moved over the depositing mold and to deposit fibrous material reinforcement and/or meltable material; (b) depositing fibrous material reinforcement embedded within meltable material onto the depositing mold, at least one layer of a lower aerodynamic face-sheet being built thereby; (c) depositing meltable material onto at least a portion of the outer layer of the lower aerodynamic face-sheet, at least one layer of core structure being built thereby; and (d) depositing fibrous material reinforcement embedded within meltable material onto at least the outer layer of the core structure, at least one layer of an upper aerodynamic face-sheet being built thereby; wherein steps (b), (c) and (d) are performed using Additive Manufacturing technology.