Aviation training has remained largely untouched by decades of development in cognitive science. In aviation, people must be trained to perform complicated tasks and make good operational decisions in complex dynamic environments. However, traditional approaches to professional aviation training are not well designed to accomplish this goal. Aviation training has been based mainly on relatively rigid classroom teaching of factual information followed by on-the-job mentoring. This approach tends to compartmentalize knowledge. It is not optimal for teaching operational decision-making, and it is costly in time and personnel. The effectiveness of training can be enhanced by designing programs that support the psychological processes involved in learning, retention, retrieval, and application. By building programs that are informed by current work in cognitive science and that utilize modern technological advances, efficient training programs can be created. Such programs could accommodate individual differences in training, experience, and temperament, and could build upon the learner's existing mental organization. In this paper, we present a brief analysis of how training can be designed to increase the likelihood that learners will be able to retrieve and apply their knowledge when it is needed, and we present concrete examples of how these ideas are being applied in the NASA in-flight icing training program.