From a global point of view, aircraft emissions contribute by a few percentage to air pollution. Nevertheless, the continuous increase in air traffic and the awareness of new phenomena (contrail contribution to greenhouse effect, contribution of NO(x) emitted to the stratosphere to the destruction of the ozone layer, etc.) leads to specific attention being paid to aircraft pollution. The CO and HC amounts emitted by aircraft engines have already been reduced in a significant manner since the beginning of the 70's owing to a number of technological improvements. But the NO(x) emissions have only slightly been reduced. It is required to take account of other pollutants such as CO2. In addition to technologically improved engines, fuels and structures, incentive economic measures (fuel taxing for example) on the one hand, and structural measures to improve traffic management (congestion reduction for example) should be studied Therefore, an integrated approach including all actors involved (airports, airline companies, air navigation authorities) should be encouraged. Of course, the major part of the measures relating to air transportation should be implemented at an international level. The standards of the International Air Transport Organisation are being reviewed. This review is also required by the airport authorities through AACC (Airport authorities coordination council) and by airline companies through IATA (International air transport association). In particular several European companies specified that the levels of emitted pollution will be considered as significant criteria for engine selection.
