A RAND research effort sponsored by the Office of the Secretary of Defense examined the future of the U.S. fixed-wing military aircraft industrial base. Its focus was the retention of competition and innovation in the military aircraft industrial base. The first major research task in that study involved a careful examination of the evolution of the industry structure over time, which emphasized an analysis of the role of competition and its links to innovation throughout the history of the industry. This report provides our findings and "lessons learned" from that part of the larger RAND research project. The purpose of this survey was to identify issues relevant to the current policy debate on whether adequate levels of competition and innovation in fixed-wing combat aircraft development can be maintained over future decades. The debate has arisen from two recent developments: (1) the dramatic reduction in the number of credible combat aircraft prime contractors and lower-tier suppliers as a result of extensive mergers and acquisitions-consolidation-throughout the past decade and (2) the continued reduction in the number of anticipated new development and production programs for manned combat aircraft over the same period.1.