• Speak to a physician if you have a history of cardiac or pulmonary disease or cancer.

• If you've had surgery, including eye or oral/dental, within the last month, check with your physician prior to flying.

• If you wear contact lenses, consider wearing glasses during the flight, or using commercially available lubricating eye drops, as reduced cabin humidity can cause eye irritation.

• If you have a cold or an infection — particularly ear, nose and/or sinus infections — cancel your flight. Congestion can lead to pain, bleeding and possibly a ruptured ear drum or sinus damage. Obtain a note from your physician as many airlines will not charge you for your flight if you provide a physician's note during the cancellation process. If you must fly while ill, contact your physician to ask about what precautions you should take. Find out from the airline what their policy is on those traveling while sick or who need medical assistance — some require medical documentation prior to flying.

• If you are pregnant, check with your physician before flying.

• If you are diabetic, discuss what adjustments to make to your medication schedule if you are flying across multiple time zones.

• It is dangerous to fly immediately after scuba diving. If you have been scuba diving, wait 12 to 24 hours (depending on the depths and number of dives performed) before flying.

• Place all medication(s) — both prescription and over-the-counter — and any medical supplies (insulin syringes) in your carry-on bag. Not only will they be less likely to be lost, but they will not be exposed to temperature changes that occur in the cargo/storage area.

• Bring a copy of the prescription and your physician's contact information with you in case the medication is lost or stolen. Also, know the generic names of all your medications as brand names can vary.

• Carry medications in the original bottles to help avoid security issues.

• Take along extra medication(s) in case your return trip is delayed.

• Avoid tight shoes, since feet may swell during flight. Choose shoes that you can easily take off or consider wearing sandals.

• Wear light, comfortable clothing.

• Bring a sweater or coat to cover up.

• Drink fluids before and during your flight to avoid dehydration.

• Limit your alcohol intake at least 24 hours before flying, particularly if you suffer from motion sickness.

• Avoid alcohol and caffeine, which can contribute to dehydration. Drink plenty of fluids — try to drink 8 ounces per hour — water and fruit juices are best.

• Request only bottled water or canned beverages — especially if you have a suppressed immune system — as a recent study by the U.S. Environmental Protection Agency found bacteria in the water on both domestic and international aircraft.

• Eat lightly.

• Sleep on the plane to avoid jet lag.

• Do not use an airline provided-blanket or pillow unless it is in a sealed package. An unsealed blanket may have germs from previous passengers.

• Flex and rotate your neck, back, shoulders and ankles every 20 to 30 minutes to avoid stiffness. If sitting for more than 30 minutes, get up slowly as blood may have pooled, which can cause dizziness when suddenly standing.

• Take a walk around the cabin every hour or two if flight safety permits.

• If you are pregnant, request an aisle seat and walk about the plane when this is permitted during flight. Place the seatbelt low on your pelvis to avoid fetal injury.

• If the person next to you is coughing, request to be moved if possible.

Pay attention to the safety briefs and make sure you know the location of the nearest exit.

• In the event of an emergency landing, follow the instructions of the flight crew. Before opening an exit door, check to be sure there is not a fire. If there is a fire outside the door, use an alternate exit.

• If there is smoke in the cabin, stay down. Cover your mouth and nose with a cloth or handkerchief.

• Leave personal items and luggage behind.

• Stay in your seat until the plane is at the gate — standing passengers have been injured from a sudden halt.