Reduce the amount of items on meal trays. Stock to the main and a piece of bread or a salad. No need for all these extra individually wrapped items, dessert etc.

Meals included in the ticket fare are by default vegan (should be cheaper for SAS) and if meat dish is desired then it is a special order at an additional cost.

Using hydrogen tanks in the rear of the plane, for example. This could work on shorter routes such as domestic flights or intra-Europe.

Fill up empty seats by selling affordable return trips to unknown/secret destinations. Pick the destinations among those that have low occupancy close to departure time.

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

You could offer cheaper tickets during these hours, encouraging passengers to choose more eco-friendly flights based on fuel efficient routes, altitude and time slots.