This research was motivated by the move of aero-engine manufacturers to provide services as well as products. With leasing arrangements such as TotalCare©, the aero-engine manufacturers are responsible for the operation, management and maintenance of their products while airlines pay a contracted rate for their use. As a result, aero-engine manufacturers need to minimise the cost their products incur over their lifecycle to increase profits. It is widely accepted that the greatest scope to reduce costs is in the design stage. Hence, the aim of this thesis is to create tools and methodologies for designers which will allow them to monitor the impact of design decisions on whole life cost. Two different approaches to designing for whole life cost were presented. The Life Cycle Cost (LCC) approach and the comparatively novel Value Driven Design (VDD) approach. It was observed from research literature that models for both LCC and VDD need to be tailored to specific objectives in order to keep the scope of the model manageable. This makes generic LCC or VDD models unfeasible and consequently the reuse of these models is limited. With this in mind, a methodology was developed for creating integrated analyses models which were customisable, modular and transparent so as to facilitate future modification and reuse. It used a commercial software integration package called Isight, and modular analyses modules. Model Based Systems Engineering (MBSE) was also used in the development of the integrated model architecture. Case studies were performed for both LCC and VDD approaches to allow comparison of their respective merits and flaws. Finally several avenues of future work in VDD and MBSE were discussed.