Planes overhead in SM4
Merton and Sutton, London. All 559 of its postcodes measured (22 PO boxes and other large-user postcodes left out), January to August 2026.
For Heathrow's expansion consultation, open until 22 December 2026: the planes over Merton, council by council.
From Heathrow
Planes land and take off into the wind, so the weather decides which way Heathrow flies, and that decides how many pass over SM4. Across its postcodes, January to August 2026:
On a day it flies west, 56% of days
Up to 59
a day
Of its 559 postcodes:
- 10 to 99
- 476
- under 10
- 83
On a day it flies both ways, 15% of days
Up to 37
a day
Of its 559 postcodes:
- 10 to 99
- 512
- under 10
- 47
On a day it flies east, 29% of days
Up to 65
a day
Of its 559 postcodes:
- 10 to 99
- 13
- on an edge
- 49
- under 10
- 497
Each sector's bar splits its postcodes by how many planes pass over them a day; the figure above it counts those in the busiest band the sector reaches. The list above gives the whole district's counts.
| Sector | Flying west56% of days | Both ways15% of days | Flying east29% of days |
|---|---|---|---|
| SM4 4176 postcodes | 139 at 10 to 99 | 130 at 10 to 99 | 6 on an edge |
| SM4 5154 postcodes | 128 at 10 to 99 | 153 at 10 to 99 | 13 at 10 to 99 |
| SM4 6209 postcodes | 209 at 10 to 99 | 209 at 10 to 99 | 209 under 10 |
| SM4 920 postcodes | 20 under 10 | 20 at 10 to 99 | 20 on an edge |
On an edge: the postcode is on the edge of a flight path, where a few metres decide whether a plane counts as overhead, and the fewest and the most within 100 m of it fall in different bands.
What counts as overhead
Overhead means more than halfway up the sky (48.5 degrees or more) and below 7,000 ft, the CAA's definition of an overflight (CAP 1498). A day counts as one way when 80% of its flights used that way. PO boxes and other postcodes for organisations that receive a lot of post are left out: they sit at a delivery office or a business, not at homes.
Near SM4
SM3 SW20 SM1 KT4 CR4 SM5 SW19 KT3
The councils
Where these figures come from
Counted from community flight tracking, checked against the CAA's monthly totals for Heathrow. Flight tracks: adsb.lol (ODbL 1.0); Weather at each airport: Iowa Environmental Mesonet; Ground heights: Contains OS data © Crown copyright and database right; Postcode positions: ONS National Statistics Postcode Lookup (OGL). Licence: Open Database License (ODbL) 1.0.