My personal CO2 emissions should be listed on my boarding pass in the app for each flight.

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

Only one checked-in baggage with Plus ticket

Give more Eurobonus point to sustainable destinations, by ranking airports and/or destination

Adjust flying height to reduce contrails

Stop giving away perks for children. They'll all end up in the garbage anyway.