The development of aircraft involves many actors throughout the supply chain. The rationale for forming partnerships and selecting suppliers ranges from risk sharing, knowledge access to price and reliability of supply. The product, subject to many design drivers, uses a wide range of technologies in highly optimized conditions with ever-increasing cost pressure. The lifetime for technologies and subsystems, clockspeed, ranges over more than an order of magnitude between software functionality and airframe life while the functional integrity of the product has to remain throughout its life. This is implying a strong need for efficient collaboration throughout the supply chain supporting product integrity throughout its life. The purpose of this paper is to show how modelling and simulation, M&S have been applied systematically as an enabler for Holistic Integrated Product Development at Saab. Early knowledge and understanding as well as ability to communicate throughout the supply chain play a critical role. The findings are based on the research program LARP (initially Lean Aircraft Research Program) and the implementation experiences from Holistic Integrated Product Development at Saab. Studied cases include the auxiliary power unit development, a collaborative project with challenging integration both on functional and physical level. Results are demonstrating e.g. the importance of M&S for successful communication and coordination between integrator and supplier. The findings further high-lights the importance of creating value at early stages of product development, including New Business Models for Aerospace& Defense, Flexible Product Development and Supply Chain Innovation. All these subjects are studied in the current phase of LARP.