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In aviation, the flight length is defined as the time airborne during a flight.
|Short-haul flight:||<3 hours|
|Medium-haul flight:||3 to 6 hours|
|Long-haul flight:||6 to 12 hours|
|Ultra long-haul flight:||>12 hours|
This definition is independent of absolute distance covered and whether the flight is domestic or international.
- Domestic/international versus flight length
Domestic flights can vary greatly in distance covered since some countries are larger than others. A short-haul domestic flight is commonly categorized as being no longer than 500 mi (800 km) or taking under one and a half hours to complete, meaning that all domestic flights within relatively small countries like the United Kingdom are short-haul. But in addition to this criterion, to be considered a domestic flight the destination airport must be in the same country as the departure airport.
- Distance covered versus flight length
A flight is typically planned to follow a direct route wherever possible to minimise flight length. For long-haul flights, the most direct route follows a great circle along the diameter of the earth. For example, aircraft travelling westward between continents in the northern hemisphere often follow paths extending northward near or into the arctic region. When shown on a conventional projection of a world map, the resulting route appears longer than a direct route would be since it is shown curved. The great-circle distance between airports may therefore give a better approximation of flight length.
However, a flight route must also take into account weather conditions, air currents, and fuel economy. A transcontinental flight in an easterly direction often takes a more southerly route than a great circle route in order to take advantage of the jet stream.
Air time versus time zones on the ground
Time on the ground will be affected by time zones. So a pilot flying westwards, or "chasing the sun", lengthens his day, and conversely an eastbound flight is shortened in terms of clock time. This does not affect the classification as long, medium or short haul.
- Short-haul flights
A short-haul flight for Cathay Pacific may be a flight between Hong Kong and Tokyo or Korea. In the United Kingdom, Air Passenger Duty is levied on all flights by the UK Treasury according to banding by distance. It defines a short-haul flight as a flight distance under 2000 miles.
- Medium-haul flights
A medium-haul flight lasts from three and six hours, for example between the United Kingdom and Egypt, which requires approximately five and a half hours to complete. Like long-haul flights, medium-haul routes can be domestic in larger countries; flights between the east and west coasts of the United States also average around five and a half hours. 
- Long-haul flights
Long-haul flights are journeys typically made by wide-body aircraft, such as Boeing 767, Boeing 777, Airbus A330, Airbus A340, Airbus A380 or Boeing 747. They involve long distances typically requiring over six and a half hours to cover and are often non-stop flights. Only a few narrow-body aircraft, such as the Boeing 757, have true long-haul capability. These aircraft are commonly used on secondary transatlantic routes.
- Ultra long-haul flight
Ultra long-haul flights are journeys typically made by long-range wide-body aircraft such as the Boeing 777-200LR and the Airbus A380, such as Dubai to Toronto and Dubai to Los Angeles by Emirates with its Airbus A380-800. Dallas/Fort Worth to Sydney, the world's longest flight, served by Qantas is an example of an ultra long-haul as well. These flights involve the longest distances flown by commercial aircraft, requiring over 12 hours to cover, and are also often non-stop flights.
Lufthansa Regional CityLine Avro RJ85, a typical short-haul aircraft
Boeing 737-700, a typical medium-haul aircraft
- List of short-haul civilian aircraft post war
- List of short-haul regional airliners
- List of short-haul narrow-body airliners
- List of ultra long-haul civilian aircraft post war
- Regional airliner
- Wide-body aircraft
- Non-stop flight
- Flight distance record
- International flight
- Dik A. Daso Doolittle: Aerospace Visionary 2003 - Page 116 "While flying west, a pilot actually lengthens his day by “chasing the sun.” Hence, there are effectively three hours more daylight than darkness on this east-to-west flight. "
- Eaves, Matthew (2008). How to Survive a Long Haul Flight. London: Mandival. ISBN 978-0-9559844-0-2.
- Thomas Cook Airlines - Prices