Since our bodies are 2/3 water, it is logical to assume that we need to drink plenty of the stuff to stay healthy. In fact, the latest medical advice is that in this centrally heated, air conditioned world, we should be drinking 2-3 litres of water a day. Failure to do so can result in itchy skin, headaches and various unmentionable internal troubles.

So it's heartening to know that when you fly American Airlines First or Business Class you get your own stash of chilled Evian bottles delivered to your seat. You don't need to keep asking for refills or hump your own supplies on board. You just sit back and drink to your own health.