Even if you have a few seats in business. The planes will be filled as usual while providing better service with almost no additional carbon footprint.

Incentivize sustainable behavior, e.g. a small reward for bringing your own coffee cup. This can also be sold by SAS in the Eurobonus store or in flight.

Reusable boarding cards for people without phones. Like the consius travelee bag tag.

Use real cutlery as disposable cutlery is not sustainable, not even wood.

In order to maximum cabin factor, offer Eurobonus tickets on all flights

Instead of serving main meals on the flight briefly after takeoff, service the meal in the boarding area. Save load, effort and waste.