In simplistic terms I've never understood why SAS does not route long haul eastbound from ARN and westbound from CPH or OSL depending on which has the biggest home market. If I were ARN based and going east, returning to CPH would be a big no and I would choose another airline and if I wanted a local connection I would choose AY. Sweden is the biggest single market of the Scandinavian countries and yet nothing operates from there and SAS have failed to exploit it.