In Scandi all tap water is great. Sell SAS water bottles onboard which are made to be reused = able to buy for points, pre-order as well. And then load tap water onboard.

Require everyone to pre-order meals, snacks and drinks so that the plane can carry just the right amount of food and drinks.

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.

Use infrared heating to melt snow, ice, and frost without using chemicals

Present sustainability data for the flight in the infotainment system, with for instance bio-fuel stats, # meals pre-selected and how much carbon emissions was saved.

Collect food waste separately, return as food for the animal farms supplying the meals, creating a true circular supply chain.