It's not often that economists turn their attention to military hardware, but Deutsche Bank has done just that in its latest world outlook. The subject is aircraft carriers and what it sees as the strange desire among a number of countries to build them.

Russia has suggested it may build up to six carriers, DB notes, while China plans one and Britain and France three between them. Like the true economists they are, DB first questions the need, saying such boats are vulnerable, make no sense for coastal defence and are for projecting offensive power over long distances. Then comes the cost:
  

"To build a serious aircraft carrier costs well above $5 billion. But then you need to build half a dozen escort vessels and the aircraft to produce a battle unit that will require upwards of 10,000 sailors. Since it is for distant power projection, to keep a single aircraft carrier group on constant deployment requires at least two and more likely three groups."

It reckons China can afford this because it only plans to build one. But Russia, even with a recent surge in wealth, is unlikely to launch a programme soon, it concludes.