Make the app as lightweight as possible. Remove images, animations and leave only the bare necessities. This saves data transfer and storage - which in turn saves energy.

Give more Eurobonus point to sustainable destinations, by ranking airports and/or destination

Let the captain thank the x number of passenger on board that added bio-fuel on the ticket.

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

Magazines and security and safety papers, is put on the sas app or screen only for long hauls to save paper

Always aim for fully booked flights; if not, find the best solution to optimize occupancy and efficiency.