Originally Posted by
craz
Its funny UA uses OY and not KF, was OY Air Belgiums code? could be a 3rd party is leasing the aircraft from AirBelgium and then leasing it to LO, or has AirBelgium taken over the Blue1 name or vice versa.
Blue1 used the KF IATA designator which Air Belgium now uses. However, Blue1 was a Finnish company, and "OY" or "Oy" is a Finnish abbreviation for "Limited Company" like LLC or Ltd.
OY IATA designator is actually used by Omni Air International, a US wetleasing company that was recently involved in the Thomas Cook repatriations and operated some flights for Air Canada after 737MAX were grounded, but that's completely unrelated.