My wife and I are travelling from London to Honolulu on UA shortly on award tickets. She is on an SAS Eurobonus award, for which SK charged GBP61 for taxes etc. I am using a UA Mileage Plus award, for which UA wanted GBP32. Same routing/planes/airports and reservations made on the same day. Why such a difference?
For BA award flights from London to Zurich, BA charged an astonishing GBP38, while AA charged only GBP20 (for the same BA flights!). GBP20 is the UK Government's Air Passenger Duty, so AA absorbed the PSC's.