According to a study carried out in New Zealand and published by the British weekly magazine The Lancet, out of 878 passengers in the 18-70 age group, who fly averagely 39 hours in 6 weeks, with a minimum of 10 hours per day, nine reported a deep venous thrombosis caused by the formation of a blood clot or of a lung embolism. This means that 1% of regular long-haul flights' passengers runs the risk...