Nuclear fuel last for much longer than fossil, and a plane can fly as long as it,s food for, so around the world in one flight.

It's also good for noise pollution

When going from A to D some times you need to transit in B and even C. Price match the most eco-friendly with the cheapest alternative in points.

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

Reusable coffee cups for take away coffee and in-flight.

Giving an incentive and getting more passengers to travel light should reduce aircraft loading and fuel consumption. Alternatively allow more cargo.

Sell biofuel to companies in bulk to lower their CO2 emissions and fast track the green transition. This would simply corporate action and speed up climate transition.