Die Flottengröße und die Häufigkeit der Flüge ist entscheidend. Eine Flugschule benötigt kein AOC.

Vergeben werden die Codes von der ICAO und im ICAO Document 8585 geführt. Beantragt wird jedoch über die nationale CAA, so dass es Unterschiede gibt. Das AIC 05/04 von Holland führt bspw. aus:

A three-letter designator is registered only for those aircraft operating agencies that, in the opinion of the state of jurisdiction, have a need for an exclusive designator. Aircraft operating agencies that either operate 7 or more scheduled international air operations per week and generate the appropriate flight plans and other related flight operations over the Aeronautical Fixed Telecommunication Network (AFTN), or carry out 14 or more scheduled domestic round trip air operations per week, are eligible for a three-letter designator.
As stated in ICAO Document 8585, radiotelephony designators should be pronounceable and phonetically suitable in at least one of the following languages: English, French, Russian or Spanish. The radiotelephony designator should, preferably, resemble the name of the aircraft operating authority or service. The radiotelephony designator should not consist of more than two words and have a total of three syllables.

nette Company call signs waren beispielsweise

• Skyrunner
• Earlybird
• Garfield

jibt et nur leider alle nicht mehr :-(