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

Encouraging standardized suitcase measurements and/or using AI to plan and stack luggage for saving space and even out the plane in regards to weight.

Waste reduction challenge: Launch an in-flight competition where the flight producing the least waste per passenger wins a sustainability award

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

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

Allow users to visualise their travel carbon footprint in-app. Include everything such as transportation to/from the home and destination, hotels.