Do not introduce Business class on intra-european flights. Plus is fair enough and very valuable for short flights and have a human price (like Norwegian and Ryanair).

Recycling the deiceing fluid.

In small airports, like Vigra, where there only 1 or 2 airplanes stand, have roofs like carports to prevent snow on plane. This will reduce amount of deicing fluid needed.

Remove the disposable earphones in SAS Go. Offer them on request. Install Bluetooth audio so that pax can connect their own wireless headphones to the IFE system.

Complimentary Arlanda Express ticket when booking a flight to/from Stockholm

Find ways to allow tax-free purchases to be done in departing airport and to be picked up at the airport were I land. It could save a lot of weigh/fuel.