Over the years much Systems Engineering effort has been focused on making development activi-ties predictable. Yet, with increasing system complexity methodology improvements have a hard time keeping up. In this paper we argue that there is a need to ensure that development methodolo-gy is flexible and that development models must be crafted for ensuring that an organization has many options open if parts of the development activities becomes delayed.
This paper addresses the challenges in crafting a model that provides an adequate representation development and meets the desired level of flexibility. The underlying case is that of fighter aircraft development. The dual-Vee model is used as a baseline, weaknesses in that model are identified and the models developed within Saab Aeronautics for fighter aircraft development are introduced and illustrated. The key element highlighted in the paper is that in order to ensure flexibility, de-velopment has to be asynchronous with integration. Lessons learned are identified and the applica-bility of the proposed models are discussed.