The environment and the impact of human activities on the environment have been at the center of attention recently, and air transportation is a contributor to environmental emissions. This paper presents a model that measures the impact of technology and policy changes on future emission levels of the air transportation. The resulting tool models the environmental performance of aircraft and the resource allocation of airlines in order to measure the fleet-wise environmental impact of changes in technology as well as to assess the degree to which policy changes on environmental metrics are achievable. The tool tracks environmental impact in three forms - CO 2, NOX and airport noise - while assuming a benevolent monopolistic airline serves passenger demand. The results reflect key relationships between emission levels, passenger demand, ticket price and aircraft technology over a period of several years.