Guides to the sky above you
Everything you need to understand the aircraft overhead.
Practical, plain-English guides to the sky over your head: how to identify the plane you're looking at, how ADS-B tracking works and why some aircraft don't appear, what altitudes, callsigns and squawk codes mean, and how to read lights, contrails and flight paths.
All guides
How to identify a plane overhead, step by step
To identify a plane overhead, note which compass direction it is in and how high above the horizon it looks, then open a live ADS-B tool…
7 min readHow ADS-B works: the signal that tells you what's overhead
ADS-B (Automatic Dependent Surveillance-Broadcast) is a system in which aircraft use satellite navigation to work out their own position…
7 min readWhy some planes don't show up on the map
A plane you can see may be missing from a live map because it does not broadcast ADS-B, because no receiver near you can hear it (common…
7 min readWhat altitude numbers mean on a flight tracker
The altitude on a flight tracker is usually barometric pressure altitude above mean sea level, not height above your house. Above 18,000…
7 min readAirliner, bizjet, helicopter or military? How to tell what's flying over
You can usually tell what kind of aircraft is overhead from four clues: its size and engine layout, its sound, its altitude and speed,…
6 min readContrails explained: why some planes leave white trails
Contrails are clouds made by aircraft. Hot, humid engine exhaust mixes with very cold air, usually around -40 °C and above roughly 26,000…
6 min readSpotting planes at night: reading the lights
At night an aircraft shows a red light on its left wingtip, a green light on its right and a white light at the tail, plus a flashing red…
7 min readAircraft noise and flight paths: why planes fly over your house
Planes fly over your house because you live under a departure or arrival path for a runway in use. Aircraft take off and land into the…
7 min readCallsigns and flight numbers: decoding the letters on the map
A callsign is the name an aircraft uses on the radio and in its ADS-B broadcast. Airline flights use a three-letter ICAO airline code…
6 min readSquawk codes explained: 1200, 7500, 7600, 7700 and more
A squawk code is a four-digit number a pilot sets on the transponder so air traffic control can identify the aircraft. Most are assigned…
7 min readHow far away is that plane? Distance, angle and sound explained
A plane's distance depends on its height and how high it appears in your sky. A jet at 35,000 ft that looks 30° above the horizon is…
6 min readWhy is a helicopter circling over my neighbourhood?
A helicopter circling one spot is usually police watching an incident, a news crew covering a story, or an air ambulance waiting to land.…
7 min readWhy planes circle: holding patterns, orbits and racetracks
An airliner circling high over one area is usually in a holding pattern, an oval racetrack flown while it waits for weather to improve or…
Reference
Look up any term in the aviation glossary, get quick answers in the FAQ, or browse aircraft identification guides.