For electric aviation drive systems engines with significantly increased power density are required. Combining the technologies of additive manufacturing of metals with the technologies of fiber reinforced composites enables hybrid structures with same or increased functionality and lower mass. Rotors or housings in hybrid design have interfaces to adjacent structures are classically made of metal. Areas for remote load transmission or with increasing distance to the rotation axis can be made of carbon fiber reinforced plastic (CFRP). The interfaces between these two materials, required for such a hybrid metal-CFRP design, can be specifically designed by using the design options of additive manufacturing to fulfill the required functions with a the most even distribution of stress possible. However, the large number of degrees of freedom of the material and the geometry leads to great challenges for engineers in the development of such structures. Within the scope of this publication, an approach for the function-oriented design of a metal-CFRP rotor for an aviation electric motor is proposed (global design). A design and pre-dimensioning method for the intrinsic interface between the materials is presented (local design).