of our fellow passengers , and usually , you really do n't have much of a choice about your seating partners . So the exposure is pure chance . But this does n't mean that you are doomed . Most respiratory viral infectious diseases -- like influenza and the common cold -- transmit via droplets contaminated with the offending microorganism when the infectious person coughs or sneezes . These droplets are propelled no farther than 3 feet and can land on an inanimate object -- such as a seat , overhead bin or seat tray -- or on your body . This is why hand hygiene is so critical and is the single most significant thing you can do to protect yourself and your family when you are traveling or out in public . Study after study shows marked reductions in transmission in public spaces when hand hygiene is practiced , and a recent study found nearly undetectable influenza particle levels after hands contaminated with influenza were washed with either soap and water or an over-the-counter gel containing at least 50 percent alcohol . Sanitize your hands before eating , drinking and after retrieving something from the overhead bin or
Editor 's note : Mark Gendreau , MD , is senior staff physician and vice chairman of emergency medicine at Lahey Clinic , Burlington , Massachusetts , and assistant professor of emergency medicine at Tufts University School of Medicine in Boston . His interests include health issues associated with commercial air travel , including transmission of infectious diseases . Dr. Mark Gendreau says swine flu is focusing attention on how to avoid getting a disease while traveling by air . -LRB- CNN -RRB- -- The novel swine flu is showing the world just how interconnected we are and how commercial aircraft can serve as vehicles of rapid disease spread . I am frequently asked : What is the risk of catching an illness while flying ? In a nutshell , the risk of getting an infection while you 're in an enclosed space such as an airplane depends upon three factors : The infectiousness of the contagious person spreading the illness ; the degree of your exposure -LRB- how close you are to the contagious person and for how long -RRB- ; and the ventilation of the space or passenger cabin . We really have no control over the infectiousness