Never seen the need for a class system? Take a long-haul flight

Usually it is annoying when you have to board an aeroplane via a shuttle bus rather than an airbridge. The exception is when the plane is a 747. That’s because, with the single exception of Lincoln Cathedral, the Boeing 747-400 is the most beautiful thing ever conceived by the mind of man. Any chance to see one at close quarters is a delight.

But aside from the engineering, the most beautiful thing about a long-haul airliner is the economic wizardry which keeps it flying. On board are a variety of seats from the sybaritic to the spartan for which people have paid wildly varying amounts of money, even though each seat will reach the same destination in the same length of time. You may find this class division offensive. However, if you were to try to make aircraft egalitarian, the system would collapse. Without the people in the front paying handsomely to sit in splendour, many of the people in the back could not afford to travel at all. An airliner is in some ways slightly socialist — it redistributes wealth through voluntary means.

This redistribution works in both directions. You can operate business-class-only flights. Indeed, if you can fill them, these are highly profitable. But there is a problem here. Business travellers prefer airlines which offer frequent flights to their destination, since they value flexibility and wish to avoid needless hours or days spent away from home. Without economy class passengers, you cannot operate sufficiently frequent flights to suit business schedules. Hence almost all long-haul airliners are symbiotically configured for mixed classes.

I sometimes suggest that we would similarly benefit from having different classes of travel on the London Underground. If the first two carriages in each train cost three times as much as the others but offered free Wi-Fi, and were furnished not with basic seats but with the sumptuousness of an Edwardian-era New Orleans brothel, you could afford to run more trains.