By outsourcing major aircraft systems to Tier 1 suppliers, original equipment manufacturers depend heavily on their supply chain to meet the growing demand for aircrafts. However, capacity constraints upstream of the Tier 1 suppliers increase the risk of schedule disruption. Discrete event simulation is commonly applied to analyze capacity constraints in manufacturing systems while analytical models assess financial investment scenarios for capital equipment. This paper demonstrates a combined simulation and analytical modeling approach to simulate the operational and financial implications of capacity constraints in aerospace supply chains. A three-tier supply chain is modeled with the option of investing to remove a capacity constraint in a sub-tier supplier. The results demonstrate how a supplier's capacity investment decisions and the increasing demand for aircrafts can affect their cash flow and delivery schedule adherence.