Recommendation—Additional Research. To reduce conflicts between the growth of aviation and environmental stewardship, NASA, the FAA, and the Environmental Protection Agency (EPA) should augment existing research by developing specific programs aimed at the following topics:

  • determining which substances identified by the EPA as hazardous air pollutants are contained in aircraft emissions and need to be further reduced

  • understanding and predicting atmospheric response to aircraft emissions as a function of time on local, regional, and global spatial scales

  • exploring the suitability of alternate sources of energy for application to aviation, taking full account of safety and operational constraints

Recommendation—Taking Advantage of Experience. The following lessons, learned since the advent of jet-powered aircraft, should be used to formulate and evaluate strategies for reducing the environmental effects of aviation:

  • Success is not easy—it requires government support and federal leadership in research and development of new technology. Establishing a strong partnership involving federal, state, industry, and university programs is essential to progress.

  • Changes in the impact of aviation on the environment occur on the scale of decades as fleets evolve; technological success in reducing adverse impacts occurs on the same or longer scales.

  • The formulation of technological strategies to reduce the environmental impacts of aviation is hampered by significant uncertainties about (1) long-term effects of aviation on the atmosphere, (2) economic factors associated with aircraft noise and emissions, and (3) the level of noise and emissions that ultimately will prove to be acceptable to airport communities and the general public, nationally and internationally.

With a final recommendation, the Committee on Aeronautics Research and Technology for Environmental Compatibility calls for leadership by the federal government to ensure the growth of an environmentally compatible national aviation capability in the 21st century:

Recommendation—The Federal Responsibility. The U.S. government should carry out its responsibilities for mitigating the environmental effects of aircraft noise and emissions with a balanced approach that includes interagency cooperation and investing in research and technology development in close collaboration with the private sector and university researchers. Success requires commitment and leadership at the highest level as well as a national strategy and plan that does the following:

  • coordinates agency research and technology goals, budgets, and expenditures with national environmental goals and international standards endorsed by the federal government

  • periodically reassesses environmental goals and related research programs to ensure that they reflect current understandings of the impact of specific aircraft emissions on the environment and human health

  • takes advantage of the unique expertise of both government and industry personnel and reverses the current trend of lessening industry involvement in NASA-sponsored environmental research and technology development

  • reallocates funds in accordance with long-term goals, shifting some resources from short-term mitigation in localized areas to the development of engine, airframe, and operational/air traffic control technologies that will lead to aircraft that are quieter, operate more efficiently, and produce fewer harmful emissions per revenue-passenger-kilometer

  • supports international assessments of the effects of aircraft emissions and the costs and benefits of various alternatives for limiting emissions

  • expedites deployment of new technologies by maturing them to a high technology readiness level (i.e., technology readiness level 6, as defined by NASA) and providing incentives for manufacturers to include them in commercial products and for users to purchase those products

Aviation is critically important to individuals, the economy, and the nation, yet the U.S. aviation industry has struggled with serious capacity issues, conflicting expectations regarding delays and environmental impacts, and long-standing federal policies on the expenditure of funds that limit support for the very research that is the key to long-term success. Vigorous federal leadership is essential to overcome funding restrictions and political issues and ensure that research and technology development proceeds as rapidly as is scientifically possible.


Congress. 2001. Conference Report on H.R. 2299, Department of Transportation and Related Agencies Appropriations Act, 2002. Congressional Record, November 29, 2001. Vol. 147, No. 163. Washington, D.C.: U.S. Government Printing Office. Available online at <>. January 15, 2002.

Lukachko, S., and I. Waitz. 2001. Environmental compatibility of aviation graphs. Cambridge, Mass.: Massachusetts Institute of Technology Gas Turbine Laboratory.

NASA (National Aeronautics and Space Administration). 2002. Technology Goals and Objectives. Office of Aerospace Technology. Available online at <>.

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