Add green flights on some departures. nothing is served on these flights, only hand luggage is allowed, but you earn more Eurobonus points if you choose such a departure.

I would use my skills in optimization and deep learning to learn what frequenzies and time schedules that maximizes the load factor of each aircraft in the fleet.

Introduce a "minimal comfort" seating class with basic amenities and reduced seat recline, allowing more passengers per flight and lowering per-person emissions.

An incentive to make longer trips rather than shorter trips would make traveling with air more sustainable.

Build in feature with EB for status ladder climbed by paying for sustainable fuel, checking in with light luggage, opting for climate neuatral meals and EV taxi to plane

Almost all passengers have their own phones/pads these days. Keep them connected with *good* wifi and IFE wont be needed, massive weight savings.