According to medical research, air travel is not advised for people with the following conditions:

1. Those with infectious diseases. For instance, people with infectious hepatitis, active phthisis, typhoid fever, and other infectious diseases cannot board a flight during a period of state-specified isolation. People suffering from chickenpox are not allowed to fly before they have fully recovered.

2. Those with a neurological disorder. For example, patients with epilepsy and other neurological disorders who may suffer an acute attack during a flight are advised not to board a flight.

3. Those with a cardiovascular disease. As a cardiovascular disease may recur or worsen due to the slight hypoxia in the sky, patients with cardiac insufficiency, myocardial ischemia, myocardial infarction, or severe hypertension are generally advised not to board a flight.

4. Those with a cerebrovascular disease. For instance, patients with cerebral embolism, cerebral hemorrhaging, and brain tumors are prohibited from boarding a flight as the roar, turbulence, and hypoxia when the plane takes off or lands may worsen these conditions.

5. Those with a respiratory disease. For example, patients with emphysema or pulmonary heart disease are advised not to board a flight due to maladjustment to the environment on the plane. If a patient suffers from pneumothorax or bullae, his or her disease may be aggravated due to gas expansion during the flight.

6. Patients cannot board a flight after ten days of undergoing gastrointestinal surgery. Patients who suffer from gastrointestinal hemorrhaging can also not board a flight within three weeks of the bleeding stopping.

7. Those with serious anemia. People whose HGB is less than 50g/L are advised not to board a flight.

8. Those with ear or nose diseases. Patients with acute exudative inflammation in their ears or nose, or patients who have recently undergone middle ear surgery are advised not to choose air travel.

9. Women who are heavily pregnant. Air pressure changes during flights may cause premature delivery among pregnant women. Those who are more than 35 weeks pregnant are advised not to undergo air travel.

Due to increased progress in aviation technology, taking a flight is a very safe and comfortable way to travel. For passengers who are elderly, pregnant, have a minor heart disease, hypertension, or asthma, air travel is much safer and more comfortable than other ways of traveling. Air travel is especially suitable for the elderly, weak, sick, or disabled because it is fast, stable, comfortable, and fully equipped with health care facilities and services. However, passengers with certain diseases should inform the airline company before traveling so that their relevant departments can take proper measures to provide a more considerate service. For passenger safety, patients with major heart disease, cerebral infarctions, or pregnant women (who are more than eight months pregnant) are advised not to choose air travel. If needed, please contact the airline company for advice on protective measures.