I recently flew YEG-KEF-YEG and enquired at the checkin counter how much it would cost to upgrade to business (saga) class and was told that upgrades can't be processed at the airport, rather, it would have to be done by calling reservations. I tried calling reservations from the lounge and was told that one cannot upgrade once they have checked in whether it be online or at the airport. I asked about upgrading for the return segment and was told that the upgrade would be $498 CAD including taxes each which I thought was somewhat reasonable given the cost of the tickets which were $660 each for my wife and I as part of an Icelandair vacation package but also included 3 nights in a hotel and a day tour. That being said, I declined.

I should note that business class was completely empty on the outbound with Y being 80% full. On the return flight, J was 4/16 and there were also a few rows of economy comfort that were full whereas there was no economy comfort on the flight from YEG.