a better airline trolley for sorting garbage. Maybe with possibility for travellers to put in from the sides.

Use real cutlery as disposable cutlery is not sustainable, not even wood.

Taxiing from and to gates from runways should be more smooth and with less fuel - using for example AI

Use more big size bottles and not small cans/bottles

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

Donate unused food and beverages after flights and try to get closer to zero food waste.