Thanks for coming back c-w-s. Interesting points.

There are indeed so many variables, as you highlight. I guess this all deserves a thread of its own so I don’t wish to take this particular one too far OT.

But just a little anecdote by way of illustration of the surrounding complexities : at a travel industry reception some time ago, I was party to an informal chat where somebody took perverse delight in telling a commercial manager employed by the carrier he had just travelled with, that there were so few passengers on his flight that “there is no way you can make money like that ....” The manager asked calmly what the route was, and then responded by saying “hmm .... low passenger loads are never ideal, but that particular route just happens to be our best performer in terms of cargo revenue”. So .... yes .... many layers, of which many folk can often be unaware.