Despite all the statistics showing how safe air travel is, I do fear flying. I'm one of the many worried fliers overcome with anxiety and stress whenever air turbulence shakes the plane enough for us to imagine that a crash is imminent.

But even if you're one of those cool cucumbers that irritate me so when I fly, you should still know that some discomforts, and even genuine dangers, are associated with flying.

Motion sickness from air turbulence. Minimize queasiness by getting a seat in the more stable middle section of the plane. Also consider using Dramamine® or Benadryl® to alleviate these symptoms.

Ear and sinus discomfort or pain. These pains, which can be quite sharp, are caused by differences in the air pressure inside the middle ear and outside in the cabin, mainly while the plane descends. This discomfort can typically be overcome (or at least lessened) by swallowing repeatedly, chewing gum, or yawning. Another effective maneuver is a short, forceful expiration while the mouth is closed and the nose is pinched shut. (One caveat here, however: People with ear, nose, or sinus infections might consider delaying air travel, since an inability to equalize air pressures may worsen these symptoms.)

Shortness of breath. Individuals with severe anemia, lung disease, or heart disease may be troubled because of the lower oxygen content of cabin air.

Travel after some recent operations. Recent abdominal surgery, for example, or treatments for a detached retina, may require you to obtain clearance from your surgeon because air or other gases might have been introduced into body cavities during the procedure. A sudden drop in cabin pressure might cause trouble.

Jet lag. After long flights, jet lag can disturb sleep patterns and cause physical fatigue and emotional distress. Be careful about driving a car shortly after arriving at your destination. Some travelers report that the hormone melatonin, if taken exactly according to a certain schedule, can help to normalize sleep patterns during travel.

Deep-vein thrombosis or blood clots. This condition, which can result from sitting in a cramped place for long periods, can lead to a deadly pulmonary embolus or blood clot, which can break off and travel to large vessels supplying blood to the lung. You are at greatest risk for this condition if you:

• are pregnant
• are elderly
• have a history of prior deep-vein thrombosis
• have other circulatory problems
• have heart disease

The danger of developing a blood clot may be reduced by walking in the aisles periodically if possible. Those with a prior deep-vein thrombosis may also be helped by wearing compression stockings during the flight.

Getting swine flu or another infection during the flight. Some persons worry that breathing the cabin's recirculated air will expose them to viruses sprayed into the cabin air when sick passengers cough or sneeze. The recirculated air on an airplane, however, is carried through fine filters that remove almost all viruses and bacteria. In fact, one research study showed that passengers on short flights developed no more colds than those traveling in plane cabins supplied with fresh air.

The risk of a viral infection, however, is increased with longer flights and by sitting within two rows of an infected passenger. Still, the risk is no greater in an airplane than it is when spending time in any confined space like a train or classroom. Just as in other circumstances, your best protection against a viral infection is to wash your hands and to avoid touching your nose, eyes, or mouth during the flight.