Whenever I looked at Air Finland's ops over the years it always struck me how little utilisation they always got out of their 757 fleet, they never seemed to have picked up much work, despite which other Scandinavian charter carriers came across to Helsinki to pick up holiday flight work, to the extent of having based aircraft. You could tell this low utilisation by the way that they turned up periodically doing subcharters for other operators, but it's a long and expensive positioning run from Helsinki down to the main Western European departure countries to do a couple of substitutions.
A key market for any Finnish leisure carrier is Helsinki to the Canary islands. This long diagonal is about the longest run you can do within Europe, in winter there are multiple departures every day on the route. It's 2,600 nm, about a 6 hour flight time, and that's a push for an A321. For this reason, Finnair also have had 757s in their fleet for many years in charter configuration, as well as A321 for shorter European trunk scheduled routes. The peak on this route is in winter.