To be fair, that's what most people call them.

Hardly anyone says "British Airways". They're just called BA, like you'd say the US, instead of United States.

I'm not from the UK, but I understand if the abbreviation doesn't make initial sense to someone outside Europe.

Sadly it's only an American thing! Wish they would expand to Europe because it sounds amazing!
Though we don't have Amazon either, so maybe there's not as big a need for it but still. I usually find that my local book store is able to order home any books they don't have in stock!