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

Make a “code-share” cooperation with train providers, to allow for booking a ticket from A to B with combined train-plane modality and same benefits as connecting flight

Develop lightweight, recyclable cabin materials and onboard items to reduce aircraft weight and waste.

A lot of ground equipment is still driven by internal combustion engines, and can be upgraded to run on electric instead for better efficiency.

Mount small blades on the side of the wheels to make them spin by themselves before landing to reduce tyre wear upon contact with tarmac.

Implement biometric boarding and baggage tracking using facial recognition and RFID for faster boarding, reduced delays, and improved efficiency.