Not that Greenpeace actually puts it that way, they manage to get it the wrong way around:

Flying in Europe up to 30 times cheaper than train, says Greenpeace

The report is here and the facts are pretty much what we’d expect. Train routes of a couple of hours - Zurich Vienna say, Lisbon Porto, are highly competitive with flying. Longer distances the flight seems to become progressively cheaper.

Of course, Greenpeace then gets this the wrong way around. They think that rail should be massively subsidised so as to make it cheaper for consumers than flying. Which is really very odd indeed. Because if flying is cheaper then it must be true that flying uses fewer resources than trains.

Especially since European rail systems are all massively subsidised already and flying isn’t - indeed it’s done by profit making companies. Sure, there’s the not having to pay tax on emissions - but even that’s not quite true. Air Passenger Duty on flights from the UK is deliberately set at a rate to cover that. Flying’s still cheaper. And, yes, British trains at least pay red diesel prices, largely untaxed that is.

One aspect of this is that a train is an expensive piece of kit, just like a plane is. So, if it takes 24 hours to get somewhere - cross-Europe can do by rail - then that expensive piece of kit is tied up transporting that one load for 24 hours. Instead of the three hours perhaps for a plane.

But those sorts of details we simply don’t need to worry about. We’ve prices to inform us. All resources used in doing something are in the price. More expensive forms of transport therefore use more resources. Trains use more resources than planes because they’re more expensive.

And Greenpeace, in the name of saving resources, wants to get us all out of planes and into trains. Yes, of course we know Greenpeace was set up by addled hippies. But we weren’t sure they were this addled. Let’s expand resource use to save resources? That’s some strong acid you’re using there.