Design and manufacturing engineers engaged in the conceptual and detail design stages of an aircraft have an ever increases number of tools and resources. However, these tools deal mainly with the physical structure and properties of the aircraft. Recently an increased effort has been made to take into account the producibil-ity and cost of an aircraft during the design phase.One of the tools being used by Lockheed Martin Tactical Aircraft Systems to accomplish this is Discrete Event Simulation. This form of simulation models dynamic production, information, and material flows. It enables an engineer to have greater visibility into the effects that he/ she makes on the overall aircraft production system. Machines and processes with different cost, speed, quality, and maintenance properties can be analyzed with respect to the system to justify their inclusion. Schedules can be examined to determine the most profitable maximum production rate and the rate at which production should be built up and reduced. Additionally, many other types of simulation analyses possible.Discrete event simulation has been integrated into the JSF design effort to assist in the exchange of data between departments at the detailed level required to build meaningful models. Early returns of model results have been used to reduce capital expenditure plans and production cycle times.