For meals, have condiments provided by request, and not automatically given to passengers. So many food items are unnecessarily thrown away.

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

For flights with a lot of empty seats, open more award seats short time before departure.

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

Implement the potential to offset carbon footprint by CDR technologies like enhanced rock weathering;

Use larger packages for the most consumed drinks, instead of handing out endless amounts of cans (less garbage, less weight on board) .