Health Issues
Common ailments like head colds, sinus pain, or fevers can cause considerable discomfort when flying. If you are unable to postpone your trip until you are feeling better, make sure you drink plenty of fluids during the flight and use a decongestant or nasal spray prior to take-off and landing.

Deep Vein Thrombosis (DVT)
Mainly affecting the veins in the lower leg, DVT occurs when a clot forms in the larger areas of the veins in the affected area. The clot can interfere with circulation in the area, and can break off into the blood stream, lodging in the heart, lungs or brain, causing severe damage to the organ.

Avoiding DVT is as simple as exercising your legs while seated and going for a walk at least once an hour. It's also recommended that you avoid dehydration by drinking plenty of water and other fluids (excluding alcohol and coffee). People with a family history of DVT, and pregnant women should discuss preventative measures, such as compression stockings, with their doctor prior to flying.

Travelling with Medications
Before travelling overseas, it's advisable to check with authorities on the regulations relating to the use of required medications. Carry all your medications in your hand luggage along with a letter provided by your doctor, listing details of your condition and treatment. This information will also assist cabin crew or doctors who may need to treat you during your flight.

Flying while Pregnant
Pregnant women flying domestically and having a normal pregnancy do not need medical clearance. However, international travel is not permitted after the 36th week of pregnancy. Passengers expecting a multiple birth or having complications will need medical clearance for both domestic and international travel.