I would use my skills in optimization and deep learning to learn what frequenzies and time schedules that maximizes the load factor of each aircraft in the fleet.

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.

In M class on Intercontinental flights reduce the usage of plastics, ask the passenger to keep their glass for the entire flight before collecting it for recycling.

Only one checked-in baggage with Plus ticket

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.

Make the trip not just climate neutral, but climate positive by compensating with 2x biochard. Fly shame to fly pride!