Yesterday I flew EI from LHR to BHD. I was happy to consider the BoB option and have used it before on EI and U2, however, I was not happy when told the £10 I handed over to pay for the €5 drink would result in my change being in €. I thought they must be short of change so offered to pay with a card then was told the price was still €5 and my card would be charged in €! Why????? What happened to £? Can they just pick any currency?
EI flying from BHD to LON is a cabotage flight (exercising EU rights) and it’s about how their onboard prime billing currency or currencies is/are setup and yes, the airline can choose.
EI is an Irish airline and it sells in € (the national currency), as does Ryanair.
BA is a British airline and sells in £ – you can pay with an Irish credit card, but will be charged in £. If BA offered cabotage flights in Europe, it could still charge in £.
easyJet sells in £ or €, but the FX rate is ridiculous, e.g. for a bacon butty you can pay either £4.50 or €6.00, whereas a proper conversion would be £5.20.
IIRC, Norwegian sell in NOK/DKK/SEK/EUR in Scandinavia and the Nordics, but also offer GBP on international flights.