In-flight medical emergencies were evaluated among passengers arriving at Los Angeles International Airport (LAX) from October 1985 through March 1986. All emergency department, LAX first-aid station, and paramedic records were examined. There were 8,735,000 passenger arrivals at LAX during the study period; 260 passengers (0.003%) developed medical complaints in flight, and of these 260, 115 (44.2%) had symptoms that lasted for more than one hour. Only 20 (8%) had in-flight physician assistance. One hundred thirty-seven (52.6%) passengers required only first-aid station treatment or signed out against medical advice, 123 (47.3%) were triaged to the ED, and 25 (9.6%) were admitted to the hospital. Seven passengers had fatal events while in flight. Most of the illnesses encountered did not require advanced medical treatment. We conclude that while in-flight medical illnesses occur more frequently than believed by airlines, true emergencies are rare. The rarity of true in-flight medical emergencies coupled with low physician availability bring into question the benefit of any comprehensive medical kit on airliners.