Commercial airline travel is so fast and easy that it attracts many people with significant underlying chronic disease. Although most airlines claim no ill effects from the stresses of air travel, airlines that fly longer routes tend to report a higher incidence of in-flight emergencies and sudden deaths than those that fly shorter routes. Reasons for these differences are discussed. The Federal Aviation Administration has recently upgraded the first aid kits carried by the airlines. Airlines must now report all untoward medical incidents to the government; this policy will permit the collection of better data concerning the true incidence of in-flight emergencies. Future studies should be oriented toward an analysis of the first aid kit's effectiveness and deficiencies. Emergency physicians are often required to make recommendations concerning the advisability of travel for patients who become ill away from home. Better criteria exist for making well-informed decisions for patients with obstructive pulmonary disease than for patients with other chronic diseases. A series of studies has suggested that physicians should recommend supplemental oxygen for normocapnic jet passengers who have a resting preflight Pao2 (at sea level) less than 67 mmHg. If available, preflight altitude stress testing should be performed on hypercapnic obstructive airways patients who request permission to fly. Poorly supported recommendations have been promulgated by several major professional organizations concerning flight advisability in a wide variety of other diseases. If these recommendations are followed strictly, people who become ill away from home can expect significant difficulty in returning home shortly after hospital discharge.