The associated research work to be presented will address issues of modelling efficiency and therefore develop insights into the nature and principles of how ATM networks are constructed and how they can be more effectively designed, by using the operational performance nature that becomes evident through the modelling. In general, the paper will present how the simulation tool a) models the network, b) implements the optimisation technic, and c) validates the approach. Consequently, this provides the platform that is then used for two real ATM networks, in both China and Europe as two selected case studies, in order to provide results. At a more fundamental abstract level, such a network is a complex system, or system-of-systems that is transdisciplinary in nature. The inherent design parameters (1) are different and diverse in nature, including aircraft, airports, and routes; the operational parameters and variables (2) are multicriteria in nature, and diverse in units and type; and causes-of-change (3) are disruptive at a mono, inter, and trans-disciplinary levels to effect multi-attribute characteristics and performance metrics that attempt to capture the impact on the network system functioning as designed and planned. Consequently, the authors intend to use the application related to ATM network performance in order to understand at a more fundamental level elements of transdisciplinary science and transdisciplinary performance both in terms of optimal level (capacity) and robustness (performance reduction and recovery).