Health Risks While Flying The pressurized, low humidity, air environment in an airplane increases the risk of sinus infections, colds, flu, ear pain, jet lag and blood clots. The humidity in this environment can drop to 10% or lower, thus drying out the mucus of the nose and throat which cripples this natural defense system. Whereas, alcohol, soda and other caffeinated drinks can dry you out, regular sipping of water throughout the flight can partially offset the effects of the...