This study explores the limits of the shift from training in real aircraft towards training in simulators. This study analyzes the considerations to determine the proper balance and identifies strategic consequences of overreliance on simulation. The author begins by reviewing historical examples of simulator development and analyzes how simulation can be beneficial to pilot training. The author then describes the drawbacks of simulation and highlights which factors are important in determining the live-simulator mix. After the author reviews how the USAF currently determines the training mix, he analyses both qualitative and quantitative research relevant to the subject. The author then uses the results to develop a model applicable to current F-35 training. The proposed model suggests which missions, and in what quantity, can be transferred to the simulator. Although this study identifies several limitations of the model, it concludes decision makers should use a prudent approach to training transfer as current understanding of the psychophysiological and hormonal responses of actual flight conditions as well as retention of complex skills are still limited. Of a number of options assessed, the author concludes the best solution is to take a gradual approach to transfer of training that allows for a more responsible assessment and management of the process.