Do not introduce Business class on intra-european flights. Plus is fair enough and very valuable for short flights and have a human price (like Norwegian and Ryanair).

Let the customer choose different carbon off-sets upon purchase of tickets. It can also include options that boost great projects.

Ensure correct recycling of plastics by unwrapping meals and plastic protected crisp breads before handing to the customer.

Implement sharkskin technology or (my own) coating to reduce air resistance and micro-drag from the fuselage.

Let the captain thank the x number of passenger on board that added bio-fuel on the ticket.

Send electronic ticket together with general flight information when sending e-mails to customers. This will cut the sent e-mail number and reduse server energy usage.