Give/sell digital bag tags to frequent flyers

Almost all passengers have their own phones/pads these days. Keep them connected with *good* wifi and IFE wont be needed, massive weight savings.

If biofuel could be bought/added with points, people could spend their "soon-to-be-expired" points on biofuel rather than something unsustainable.

Introduce a "minimal comfort" seating class with basic amenities and reduced seat recline, allowing more passengers per flight and lowering per-person emissions.

For every mile the aircraft flies overseas, SAS commits to a certain amount of plastic being removed from that ocean.

If you reduce the allowed weight for luggage from 23 kg to 15 kg or so, people might start to think if they really need all that stuff with them.