I mused about such issues 30 years ago. Simple solutions are:

a) abandon all but absolutely essential short haul air travel using instead electric rail. Steel on steel is 30 times more energy efficient that planes. For absolutely essential short haul use prop-jets
b) For long haul where there is no convenient alternative to air travel for some purposes/people (bring back the sailing ship?) it is better to trunk route large aircraft hub-to hub. First Class /Club class should disappear.

Since predicting floods is useless unless you built arks, I have spend 25 years "building arks" beside railways in the South of France. It's great.

Well if you ever want to lend me one of those arks .... :-)

The French I think have got it made - TGVs running on nuclear electricity.

Hello Euan,
You can rent them
http://www.riviera.fr/rentals

I asked the questions. Where did people go on holiday before cheap air travel and how did they get there? Answers: French Riviera and trains. The above link shows a sample of the options. My wife and I have 7 more.

They look lovely - exactly what I had in mind. Vive la France.