Question about flight numbers
There seems to be at least two flight numbering formats in circulation. Particularly for some of the loco's. For example I regularly fly FR2905 but on some websites it's listed as FR04KM. I never see the second format in any airport or on any booking emails or documents but on some websites when searching for flight info I can only find it using the latter code. What is the second format FR04KM? Some sort of airline internal reference?