Adopt single-engine taxiing to save fuel during ground operations.

Introduce an option during the booking process for passengers to offset their carbon footprint by contributing to environmental projects, with SAS matching portion of it.

Free reebooking to earlier flight when avilable. Result in filling up seats, and making it more likely to fill up seats on later flights

Make flight space available for package distributors ex. DHL for a fee. Might save their flight and truck if packages can go with regular airplanes.

Collaborate with public transport companies at popular destinations to reduce car usage.

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.