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

Sponsor projects that can help build renewable energy sources, like wind mills, solar panels. Additionaly work with selected airports on becoming carbon neutral

Digital, reusable RFID bagtag instead of paper stickers.

Not handing out napkins under every drink.

Create an ability to share a seat in your car with other passengers on the flight. It's better than everyone riding their car.

Collaborate with public transport companies at popular destinations to reduce car usage.