Major improvements have been made in aircraft noise emission, but there is still more to be done. We are increasing the number of new low-noise aircraft, and practice methods of flying to reduce noise as much as possible.
With advances in technology, the noise level of jet engines in aircraft has improved greatly in recent decades. For example, the noise of the mid sized Boeing 767 aircraft is 20 decimals lower than the DC8 and Boeing 707 made in the 1960s, which is about the same size. This is about 1/4. In addition, JAL will be introducing the new Boeing 787 (in service from fiscal 2012), which is about the same size as the 767, but produces about 40% less noise on take-off.
Research has been conducted into various methods of flying to reduce noise for areas around airports during take-off and landing. For example, when there are residential areas near airports, efforts are made to rise in altitude as much as possible when taking off, or to turn to avoid residential areas to lessen the noise impact on the ground. Also, the timing of lowering the landing gear and flaps (wing flaps) is slowed when landing, reducing air resistance and thus reducing noise.