The design and evaluation of modern Air Force cockpits is an extraordinarily complex process that involves many empirical and analytical activities. The Tactical Aircraft Cockpit Study (TACS) has pursued the development of a crew system concept for a mid-1990, single seat, air-superiority fighter and has wrestled with the practical application of existing and evolving design methodology. This paper summarizes the experiences of the TACS research team in terms of design ideas and methodology. Methodology topics discussed include requirements for mock-up or design aid fidelity, the role of pilots as subjects in evaluation experiments and the need to identify mission requirements as crew system design drivers at an early stage in the program. In addition, several specific cockpit design concepts that were evaluated during the course of the program are discussed.