ABSTRACT
There has been tremendous progress reducing aircraft noise since the problem peaked with the introduction of the turbojet engine for commercial aviation in the 1950s. Significant growth in air travel during the 1960s caused public concern over noise and emissions. Government-funded research programs were initiated, aimed at reducing the environmental impact of air travel, followed by regulations. Regulations are based on what is technically feasible and economically viable. Aircraft noise levels have been reduced by over 20 dB since the 1960s.
