Airsickness

Airsickness is a sensation which is induced by air travel. It is a specific form of motion sickness, and is considered a normal response in healthy individuals. Airsickness occurs when the central nervous system receives conflicting messages from the body (including the inner ear, eyes and muscles) affecting balance and equilibrium.
Whereas commercial airline passengers may simply feel poorly, the effect of airsickness on military aircrew may lead to a decrement in performance and adversely affect the mission.
The inner ear is particularly important in the maintenance of balance and equilibrium because it contains sensors for both angular (rotational) and linear motion. Airsickness is usually a combination of spatial disorientation, nausea and vomiting.
Signs and symptoms.
Common symptoms of airsickness include:
Nausea, vomiting, vertigo, loss of appetite, cold sweating, skin pallor, difficulty concentrating, confusion, drowsiness, headache, and increased fatigue. 
Severe airsickness may cause a person to become completely incapacitated.
Risk factors.
The following factors increase some people's susceptibility to airsickness:
Prevention.
Travelers who are susceptible to motion sickness can minimize symptoms by:
Treatment.
Medication.
Medications that may alleviate the symptoms of airsickness include: 
Pilots who are susceptible to airsickness are usually advised not to take anti-motion sickness medications (prescription or over-the-counter). These medications can make one drowsy or affect brain functions in other ways.
Non-medication based.
A method to increase pilot resistance to airsickness consists of repetitive exposure to the flying conditions that initially resulted in airsickness. In other words, repeated exposure to the flight environment decreases an individual's susceptibility to subsequent airsickness. Recently, several devices have been introduced that are intended to reduce motion sickness through stimulation of various body parts (usually the wrist).
Alternative medicine.
Ginger.