AirportsHow the distance is worked out
The calculator uses the coordinates of the two airports and finds the shortest path over the surface of the globe, called the great-circle distance. On a flat map this path looks curved. That is why a flight from Delhi to New York passes far to the north, over Central Asia and the Arctic region, and not straight across the map.
Why real flights are longer
Aircraft follow air routes, avoid some airspace and bad weather, and circle when an airport is busy. The distance flown is usually a few percent more than the great-circle distance.
About the flying time
The time shown is a rough guide for a direct jet flight: the distance at about 830 km an hour, plus half an hour for climbing and landing. Winds change it a lot. Flights towards the east are often faster than the same route towards the west. A time is shown for any pair of airports, even when no airline flies directly between them.
Kilometres, miles and nautical miles
Aviation measures distance in nautical miles. One nautical mile is 1.852 kilometres, or about 1.15 ordinary miles.