Flight Codes
Flight codes are the identifiers that are used on a flight schedule. Flight codes typically include the 2 character IATA airline designator code along with the flight number. Through a code sharing agreement, participating airlines can use a common flight code for several different reasons.

One of these reasons in connecting flights. This way customers can have a clearer routing by booking under one flight code rather than having to book their trip using several different flight codes. Another reason for code sharing is to allow two airlines to fly the same route which helps to increase the frequency of flights. The final reason is that code sharing allows airlines to display their flight codes on a route that they don’t operate in with their own aircraft.

Code sharing was originally started in the airline industry in the year 1990 with the combination of the Australian airline, Qantas Airways and American Airlines. These two carriers signed a cooperative services agreement so that a single flight could be jointly marketed by both the airlines. Today sharing flight codes in common with many different airlines and most companies have at least one alliance.

The International Air Transport Association or IATA assigns the two character designator at the start of flight codes. For commercial purposes these designators are used to identify the airline. Some uses for these designators include reservations, timetables, tickets, tariffs, air waybills and airline interline telecommunications. There are three types of these designators including unique, numeric/alpha and controlled duplicate.

The second half of flight codes is made up of a flight number. This is attached to the IATA designator to identify particular flights. This number isn’t the same as the tail number on the airplane. Typically even numbers will be given to eastbound and northbound flights while odd numbers will be given to westbound and southbound flights. During the day there may be an increase in numbers if a destination have multiple flight each day.

Often times long-haul or premium flights will have three or less digits for the flight number. Regional affiliate flights are typically represented by four digit flight numbers between 1000 and 4999. For flights that are operated by more than one airline with flight codes being shared then they are generally numbered above 5000. Should a flight suffer a crash or a serious incident then that flight number is taken out of use.