Ideally it should be supported without deficit or profit by its users. A lot of these old services also accumulate inefficiencies over time that should be pruned from time to time

An old colleague of mine worked at a different office - he got fed up of the rat run and took a job within a stone's throw of Stansted Airport - close enough that a hotel or carpark shuttle bus covered his route.

He couldn't be arsed with London and Essex house prices so he bought his house near Shannon (yes, in the Republic of Ireland) and commuted by plane every day. The major problem with that was if he didn't book a flight when they were released (where it was about fifteen or twenty quid return!), or if there was a short notice job came in that changed his hours, he was royally fucked and it cost him a fortune.

I should imagine his carbon footprint was somewhere between "Chinese concrete factory" and "literally burning petrol in the back garden for a laugh".

A friend of a friend did something similar in east London - couldn't be holed with the London house prices so got a place in some Paris suburb and commuted by train most mornings, only staying over if there was a staff night out or a late working task planned.

...and I sometimes complain about my ten mile commute.

Can hardly even fly to another Canadian city without it costing an arm and a leg.

Be tempted to look south my man

Planes don't have to maintain the sky, but trains need to maintain the rails.

Essentially any costs that can be externalized & paid by the public with air travel have been, like maintaining airports, etc.

Privatised railroads

It's pretty immoral in the current day and age, but it is something that should be made (near) impossible with better regulation until it can be done with a reasonable carbon cost

Absolutely mental regarding the cost of public transport in most of Blighty...