After 1. Sep, AFKLM will most likely want to streamline their services onboard, which means contracted lounge access at outstations + fast track should be implemented again,

they can just share the same contract deal with AF KL, that would likely to be cheaper than today. maybe no one will get wifi for free or msg free will be offered like AF does today?

and for most SK short haul, it would be a tricky situation for SAS to operate a premium economy product when passengers from the rest of the Europe would expect a blocked middel seat and business class service (maybe with a hot meal service ?).

AF KL would have more to say in this as SK will first serve as a feeder to CDG and AMS from Scandinavia, as it would take time for CPH to become a (real) hub (feeding into potential Longhaul to Longhaul connecting pax as well).

One concern would be SAS Plus allows flexibility for them to either have 1 row or 20 rows of Plus, the only difference they do onboard is to take payment for snacks and drinks or serve them for free. But Business class with curtains and proper meal services would require catering changes, and extra training for their staff. It would be unlikely SAS will introduce a proper business class seating, the realistic version would something the likes of KLM business with just a meal box, which is similar to what SAS has today.

For SAS go, AF KL serves alcohol and a light snack item in economy as well. SAS can choose to do this or not, free alcohol will remain unlikely with Scandinavian regulations in place, but maybe one polar roll / disgusting ciabatta for all? This won't be SAS main priority once they had time to reorganize their route network.

What would be the point of having 3 hubs if no longhaul will be departing from ARN and OSL, they will unlikely to make money solely on intra European connecting pax, one potential would be to work with other Skyteam airlines by facilitating routes from Asia and US while they can codeshare and delegate transfer pax from their hubs in ARN and OSL, while SAS solely focusing on building CPH with all longhaul operations.

One such route could be Delta JFK - OSL JFK -ARN while SK remains at EWR as slots times are tricky until SK can make JFK viable before moves completely to JFK and drops EWR altogether.

For the Asia front, PVG - ARN could be of interest for MU China Eastern as they did operated the route for a while competing with Air China before the pandemic, and ARN can help with feeder traffic. China Eastern also owns shares in Juneyao airlines which could be wanting to expand to secondary European destinations so OSL could be on the table for them to negotiate, Xiamen airlines is a boutique airline focused on premium traffic which is unlikely to work with SK right away, Korea Air will be merged into Asiana (star alliance) once approved.

A joint venture for AF KL VS SK Asia - Europe routes will be likely for SAS to join after the transatlantic joint venture first in place.

Singapore and Thai should remain SK partners otherwise SAS would have difficulties capturing the main customer base who just needs to holiday in Thailand and would expect to be able to connect elsewhere in Thailand.

All other Skyteam partners look rather uninteresting at the moment, unless strategic partnership can be made.

Scandinavians do not holiday elsewhere other than Spain, these routes are always full and will remain.

Routes network would be restructured quiet heavily after summer season, as frequencies need to go up in CPH, and unprofitable routes from ARN and OSL will most likely be dropped.

CPH would be stepping up their Lufthansa groups hubs representations as they will need to compete, and these routes from ARN and OSL will be thinned out to a minimum.

For ITA and Air Europa, (for Italy and Spain), codeshare and frequency collaborations will be likely though most traffic down to warmer parts are point to point, unless ITA want to gain feeder from Scandinavia, but that would require business bearing sense which ITA currently does not have, things hang in the air like a limbo.