Instead of opt-out for food on the plane plane that is included in ticket, make it opt-in.

Use travellers feces from flights as a bioproduct. As fuel or to something else useful.

Ensure correct recycling of plastics by unwrapping meals and plastic protected crisp breads before handing to the customer.

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

Keep your good clients - minimum 10 years as gold member gives you gold for life. Not necessarily 10 years in a row. Now 18 years with 1 missing in the middle = no go

Stand up seats for shorter flights.