Vehicle design is a complex process requiring interactions and exchange of information among multiple disciplines such as fatigue, strength, propulsion, survivability, safety, thermal management, stealth, maintenance, and manufacturing. Simulation models are employed for assessing and potentially improving a vehicle’s performance in individual technical areas. The vehicle’s characteristics influence the performance in all the different attributes. Challenges arise when designing a vehicle for improving mutually competing objectives, satisfying constraints from multiple engineering disciplines, and determining a single set of values for the vehicle’s characteristics. It is of interest to engage simulation models from the various engineering disciplines in an organized and coordinated manner for determining a design configuration that provides the best possible performance in all disciplines. This paper presents an approach that conducts optimization analysis for a complex system by coordinating operations and exchange of data and information through a network of optimizations. The presented approach provides an organized and seamless environment that captures the implications of design changes from a particular discipline to all other disciplines. It is possible to share design variables among disciplines and thus identify the direction that design variables should follow based on objectives and constraints from multiple disciplines. A rotorcraft example that demonstrates the operation of this integrated design environment is presented. The mass of the gearbox support frame is minimized at the system level while at the same time the performance in structural dynamics and crashworthiness is optimized.