Book excerpt: In June and September 1990, the Transportation Research Board conducted a series of workshops on methods of forecasting civil aviation activity. Organized at the request of the Federal Aviation Administration, these workshops brought together experts from various sectors of aviation to discuss indicators of fleet activity, modeling and forecasting techniques, and future trends that could affect the demand for aviation facilities and services. The purpose was to examine methods and practices used by FAA and others and to identify ways in which the reliability and utility of forecast products could be improved. Three separate workshops were held, each dealing with a particular sector of civil aviation: business and general aviation, regional and commuter airlines, and major air carriers. This Circular contains the reports prepared from the discussions in the three workshops and two appendices which discuss, respectively, demographic forecasting models and Civil Reserve Air Fleet (CRAF) impacts on commercial aviation.