Robust control design for complex flexible structures involves many consecutive essential steps. Additionally, many design parameters arise, which turn design optimization into a cumbersome and difficult task. This paper presents a comprehensive robust ℋ∞-optimal control design methodology for this class of systems. It relies on a pragmatic approach: The control engineer produces an initial design and reuses it in subsequent design iterations and parameter optimization. The methodology is illustrated by a large transport aircraft model and shows high potential to obtain and tune robust high-performance controllers. Expert knowledge and design decisions are introduced in a natural, clearly structured way, while control engineers are relieved from repetitive design tasks which are safely automated.