Environmental degradation caused by emissions from aircraft is likely to increase in severity with the growth of flying. Until recently, such emissions were considered to be insignificant, but during the last five years, this view has been reversed. The complexity of the effects of pollution in the atmosphere has now been realised, at least qualitatively. The known consequences of some of the main emissions are discussed along with current environmental legislation and pertinent UK Government policy with regard to aviation. Recommendations are given for some future UK transportation-by-aircraft policy objectives that would safeguard the future of our, as yet, relatively pollution-free skies.