Wellington - A group of medical specialists has provided an answer to a dilemma that has faced flyers since the Wright brothers took to the air in 1903 -- is it okay to fart mid-flight?The experts' recommendation is an emphatic yes to airline passengers -- but a warning to cockpit crews that breaking wind could distract the pilot and pose a safety risk.The study concluded that anecdotal evidence that flying increases flatulence is not hot air, finding that changes in air pressure at altitude result in the gut producing more gas.When Danish gastroenterologist Jacob Rosenberg encountered the malodorous problem first-hand on a flight from Copenhagen to Tokyo, he enlisted some of the finest minds in his field to address the issue.The result was an in-depth review of scientific literature on flatulence, looking at issues such as whether women's farts smell worse than men's (yes), what causes the odour (sulphur) and how often the average person passes wind every day (10).The bottom line, according to the 3,000-word study published in the New Zealand Medical Journal on Friday, is that airline passengers should ignore the social embarrassment of breaking wind and "just let it go"."(Holding back) holds significant drawbacks for the individual, such as discomfort and even pain, bloating, dyspepsia (indigestion), pyrosis (heartburn) just to name but a few resulting abdominal symptoms," the study found."Moreover, problems resulting from the required concentration to maintain such control may even result in subsequent stress symptoms."The authors -- five gastroenterologists from Denmark and Britain -- said that while passengers may experience poor service from the cabin crew as a result of their decision, the health benefits outweighed any negative impacts.However, they said the cockpit crew faced a lose-lose situation."On the one hand, if the pilot restrains a fart, all the drawbacks previously mentioned, including impaired concentration, may affect his abilities to control the plane," the researchers said."On the other hand, if he lets go of the fart, his co-pilot may be affected by its odour, which again reduces safety onboard the flight."The authors canvassed a number of solutions to the issue of flight-induced flatulence, including using methane breath tests to screen wind-prone passengers from flights, but rejected them as impractical.They did, however, note that the textile covers used on seats in economy class absorbed up to 50 percent of odours because they are gas permeable, unlike the leather seats in first class.They suggested airlines could improve the odour-eating properties of the seats and issue special blankets and trousers to passengers to minimise mid-air flatulence."We humbly propose that active charcoal should be embedded in the seat cushion, since this material is able to neutralise the odour," they said."Moreover active charcoal may be used in trousers and blankets to emphasise this effect." Air New Zealand declined to comment when asked if it would adopt such measures.