The invention relates to a rotary- or fixed-wing aircraft comprising one or more rotors and/or one or more propellers, in which the rotor(s) and/or propeller(s) are rotated at a variable or constant speed by at least one shaft (Rp1, Rp2, Rp, RAC, H), and the aircraft includes a power unit (GEMD) configured to propel and/or lift the aircraft by rotating the shaft. The aircraft is characterised in that: the power unit (GEMD) is a distributed electric power unit formed by multiple stacked electric power elements (Ee1, Ee2, Een), each element being adapted to confer, on the rotation shaft (Rp1, Rp2, Rp, RAC, H), a fraction of the total power necessary in order to propel and/or lift the aircraft; the distributed electric power unit (GEMD) is in direct engagement with the rotation shaft (Rp1, Rp2, Rp, RAC, H), with no movement transmission mechanism being inserted between the unit and the shaft; each electric power element (Ee1, Ee2, Een) is directly connected to the rotation shaft (Rp1, Rp2, Rp, RAC, H) and comprises at least one fixed stator (St), at least one moving rotor (Rt) and at least one mechanical or electromagnetic free wheel (RI) in direct engagement with the rotation shaft, said moving rotor (Rt) co-operating with the free wheel (RI) such as to be coupled to the rotation shaft during normal operation of the electric power unit (Ee1, Ee2, Een) and to be disconnected from the shaft in the event of the failure of the electric power element; and the rotation shafts of the moving rotors (Rt), the free wheels (RI) and the rotation shaft (Rp1, Rp2, Rp, RAC, H) are coaxial.