Finnair aren't serving blueberry juice onboard, they serve bilberry juice - the berries are not the same thing. What Finns call "mustikka" are called bilberries in English.

I think in the announcements onboard they do talk about "blueberry juice" but if you look at the English side of the carton it accurately says bilberry.

Fazer on the other hand are happy to use the wrong name, they admitted to me in an email that their chocolate bar with "blueberries" is actually using bilberries, but would prefer to use a name that's more recognisable.