Medical Emergencies on Airplanes

Medical emergencies on airplanes are fairly common, occurring on about 1 in every 600 flights, according to a 2013 study in the New England Journal of Medicine. But in only 7 percent of cases does the aircraft have to divert its route, the study found.

The most common medical complaints on flights are feelings of lightheadedness or passing out (known as syncope), followed by respiratory problems,nausea and vomiting, according to the study. 

About 1,000 passengers per year experience sudden cardiac death on commercial flights, according to a 2011 study published in the Singapore Medical Journal. More people die of heart problems on flights than in airplane crashes.

Medical emergencies can happen anywhere, but they may be more likely on airplanes because of the "lethal cocktail" of travel-related stress, disturbed sleep patterns and lower levels of oxygen. 

Pilots, too, have been known to suffer heart attacks while in flight.