If an airline runs short temporarily short of planes, e.g. too many needing engine checks, they’ll lease whatever they can from whoever they can. I was on an Air New Zealand flight from NZ to Australia many years ago that was operated in a 767 leased from a Norwegian airline.
Would never in a hundred years have expected to see that plane in the South Pacific. Also at the start of covid Germany sent a Lufthansa A380 down here to do repatriation flights.
There are any number of reasons you might see any livery at any airport.
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