In this paper the concept of the modular lightweight design as a method to combine the opposing views of lightweight-optimized- and modular product family-design is presented. Therefor specifics of these views are presented based on the use-case of civil aviation and aircraft cabins. Subsequently the concept of modular lightweight design and its concomitant benefits and challenges are outlined as well as the Model-Based Systems Engineering to assist the implementation of the approach into the product development processes for developing the modular hybrid design.