Air Travel: Aspects of health and disease related to air travel. It includes the physiologic and psychologic beneficial or adverse effects.Aircraft: A weight-carrying structure for navigation of the air that is supported either by its own buoyancy or by the dynamic action of the air against its surfaces. (Webster, 1973)Aerospace Medicine: That branch of medicine dealing with the studies and effects of flight through the atmosphere or in space upon the human body and with the prevention or cure of physiological or psychological malfunctions arising from these effects. (from NASA Thesaurus)Travel: Aspects of health and disease related to travel.Travel Medicine: Multidisciplinary field focusing on prevention of infectious diseases and patient safety during international TRAVEL. Key element of patient's pre-travel visit to the physician is a health risk assessment.Compressed Air: Air that is reduced in volume by pressure.Aviation: Design, development, manufacture, and operation of heavier-than-air AIRCRAFT.Air: The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.Lymphangioleiomyomatosis: A disease characterized by the progressive invasion of SMOOTH MUSCLE CELLS into the LYMPHATIC VESSELS, and the BLOOD VESSELS. The majority of the cases occur in the LUNGS of women of child-bearing age, eventually blocking the flow of air, blood, and lymph. The common symptom is shortness of breath (DYSPNEA).Pneumothorax: An accumulation of air or gas in the PLEURAL CAVITY, which may occur spontaneously or as a result of trauma or a pathological process. The gas may also be introduced deliberately during PNEUMOTHORAX, ARTIFICIAL.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Pulmonary Embolism: Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.Air Pollutants: Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.Air Pollution: The presence of contaminants or pollutant substances in the air (AIR POLLUTANTS) that interfere with human health or welfare, or produce other harmful environmental effects. The substances may include GASES; PARTICULATE MATTER; or volatile ORGANIC CHEMICALS.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Embolism, Air: Blocking of a blood vessel by air bubbles that enter the circulatory system, usually after TRAUMA; surgical procedures, or changes in atmospheric pressure.Air Microbiology: The presence of bacteria, viruses, and fungi in the air. This term is not restricted to pathogenic organisms.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Transportation: The means of moving persons, animals, goods, or materials from one place to another.Air Movements: The motion of air currents.Air Pollution, Indoor: The contamination of indoor air.Air Sacs: Thin-walled sacs or spaces which function as a part of the respiratory system in birds, fishes, insects, and mammals.Air Conditioning: The maintenance of certain aspects of the environment within a defined space to facilitate the function of that space; aspects controlled include air temperature and motion, radiant heat level, moisture, and concentration of pollutants such as dust, microorganisms, and gases. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Jet Lag Syndrome: A chronobiologic disorder resulting from rapid travel across a number of time zones, characterized by insomnia or hypersomnolence, fatigue, behavioral symptoms, headaches, and gastrointestinal disturbances. (From Cooper, Sleep, 1994, pp593-8)