The aircraft noise problem is an environmental “minus” that was born alongside the commercial gas turbine aeroengine more than thirty years ago. The issue came to a head in the 1960s, around the time when the number of jet-powered aircraft in the commercial fleet first exceeded the number of propeller-powered aircraft. During that decade, significant sums of money were expended in research and development exercises directed at quietening the exhaust noise of the subsonic fleet and in researching the noise of even higher-velocity jets that would have been a major problem if the supersonic transport had become a commercial success. Later in the 1960s, with the advent of the bypass-engine cycle, the emphasis was more on the noise generated inside the engine, with the large proportion of the extensive research funds necessary being provided by the taxpayers in those nations with aircraft- and engine-manufacturing capabilities.

Government action was not only limited to supplying the funds for research contracts, but major nations cooperated on a political front to develop noise certification requirements that were demanded of the manufacturers of all new aircraft produced from 1970 onwards. Coincidentally, technology moved forward and produced the high-bypass or turbofan-engine cycle, which, in reaping the benefits of the accelerated noise programmes of the 1960s, was only about one-quarter as noisy as the engines it replaced. Initially, however, the turbofan cycle was limited in its application to the new breed of larger wide-body jets, which had at least twice the passenger-carrying capacity of their forebears.