AUltra High Bypass-Ratio Engine (UHBR)Ultra High Bypass-Ratio Engine (UHBR)design and integration propulsion system for future aero engines with ultra-high bypass ratio (UHBR) engines was designed and extensively evaluated applying different numerical methods. The propulsion unit under consideration featured an engine representative, robust and highly efficient fan stage as it had been designed by DLR, as well as a nacelle and an intake designed by an industrial partner. The paper focuses on the design process with subsequent high-fidelity analysis, first of all of the full-scale fan stage, aiming at balancing all kinds of performance-related as well as structural and operational requirements under various operating scenarios. The application of efficient multi-disciplinary (MD) optimization and simulation techniques is addressed, for example, to better understand different phenomena such as fan operation under angle-of-attack conditions or rotor flutter sensitivity due to an acoustic feedback loop with the intake, which stem from the integration of low fan pressure ratio fans.