Last week's "terror plunge" to an emergency landing by a Qantas jumbo jet will have done little to soothe the intense fear of flying suffered by one in five of the UK population. Boarding an aeroplane may actually be the safest form of travel, but being stuck in a metal tube, 39,000 feet in the air, can exacerbate so many other phobias: fear of crowds, heights, confined spaces and loss of