How far does airport noise travel?

There is no single distance. Airport noise travels furthest where planes stay low for longest, which is along the approach to each runway, and much less far to the side. Where it stops on a given day depends on which way the runways are in use, on the weather and on which aircraft are flying.

The short answer

"Loud" here means above 65 dB outdoors, loud enough to interrupt a conversation.

Along the approach: the longest reach

Landing planes descend on a shallow 3° slope, so they are still low a long way out. At Heathrow we measure them at about 1,800 ft over Kew and North Sheen, 10 km from the runway, and at about 2,700 ft over Putney and Fulham, 15 km out. And because every landing on a runway follows the same straight line for the final 15 km or so, the streets under that line hear every one of them.

That is why our Kew Green sample report, for a house 10 km from Heathrow, counts 92 loud landings a day when the wind is from the west. When it is from the east, the landings come in over Windsor on the other side of the airport, and the same house counts 4 loud flights a day.

Under the departure routes

Take-offs are loudest close to the airport, where the planes are at full power and still low. After that they climb much faster than landings descend: about 300 ft for every kilometre at Heathrow, against 170 ft for a landing. They also follow set routes, which at Heathrow are corridors 3 km wide up to 4,000 ft, before controllers send them on more direct headings. So their noise is shared between several routes, and it thins out sooner as the planes climb.

How far a take-off carries depends above all on the aircraft. The Department for Transport modelled the area where a single departure is louder than 60 dB at its peak, which it takes to be about 45 dB indoors:

A single 747-400 take-off, in other words, was above 60 dB over an area almost twice the size of Heathrow's whole 55 dB Lden noise contour. The 747-400 now makes fewer than one flight a day at Heathrow, but it shows how far one heavy take-off can carry.

To the side of a flight path

Away from the line a plane flies along, noise fades for three reasons. Distance: each doubling of the distance to the plane takes about 6 dB off. The air: it absorbs sound, more or less depending on temperature and humidity. And the ground: sound travelling at a low angle over it loses more still.

Close to the line the difference is small. The Civil Aviation Authority counts a plane seen at 48.5° above the horizon as about 3 dB quieter than one directly overhead, and 3 dB is about the smallest change most people notice. For a landing plane at 1,800 ft over Kew, that angle is reached about 500 m to the side. So a house 500 m off the approach line hears nearly as much as one right under it. At 1 km to the side the plane is about twice as far away, which takes about 6 dB off before any ground effect: a real difference, though a large jet can still be loud.

What makes the distance vary

• The aircraft and its weight. Big, older jets carry furthest, as the take-off figures above show. A heavily loaded plane is also lower over the ground after take-off than a light one. At Heathrow, the area inside the 55 dB Lden contour shrank from 244.7 km² in 2006 to 142.4 km² in 2025 with about the same number of flights, as 747-400 movements fell from 135 a day to fewer than one.
• The weather. Wind and changes of temperature with height bend sound on its way to the ground. The method European airports use for their official noise maps, ECAC Doc 29, notes that beyond a few hundred metres the level from the same flight can vary by 10 dB or more with the weather. Our guide on why planes sound louder on some days explains how.
• The wind direction. Planes take off and land into the wind, so it decides which areas are under the approach on a given day, as the Kew Green figures show.
• Terrain and buildings. Hills and ground cover can change how much noise reaches a house, and buildings can shield noise from planes on the runway.
• Routes and runway use. Changes in how routes and runways are used move the noise too. Compared with 2006, heavier use of one easterly departure route stretched Heathrow's 2025 contours for planes above 65 dB south-east over Ham in Richmond.

How big the official noise contours are

Official noise maps give a sense of scale, although they average the noise over a day or a year. These are Heathrow's for 2025, produced by the Civil Aviation Authority:

The contours stretch furthest along the runway lines, in lobes that follow the approaches and the main departure routes. The UK now treats 51 dB LAeq,16h as the level at which adverse effects begin, so the area of concern is larger than the 54 dB contour in the table. Our guide to official airport noise maps explains what each measure means.

Across Europe, 2.4 million people lived above 55 dB Lden from aircraft in the 2022 round of official noise maps, and EASA estimates that 1.6 million people around 98 major airports heard more than 50 planes a day above 70 dB in 2023.

Averages also hide the days that matter. A place that hears 100 loud planes on half the days and none on the others has the same average, 50 a day, as one that hears 50 every day. Kew Green's average day has 66 loud planes, but a westerly day has 92.

If you are choosing where to live

The practical lesson is that direction matters more than distance. A house 10 km out under an approach can hear more loud planes than one 3 km from the airport off to the side of the runways. Our guide on how far from an airport is far enough turns this into checks for buyers and renters, and our free flight map for Heathrow replays real days so you can see where the planes pass.