This study's goal was to analyze aeromedical emergency medical services (EMS) endotracheal intubation (ETI) success rates for in-flight intubations, and to retrospectively compare in-flight ETI success rates with those achieved in hospital and trauma scene settings. Patients undergoing flight crew ETI during a 3-year study period were reviewed, and flight team-performed intubations were classified as in-flight, hospital (at referring hospital), or ground (at trauma scene). Flight crews attempted ETI in 302 patients, with success in 291 patients (96.4%). ETI success rates for in-flight, hospital, and ground groups were 94.2%, 96.8%, and 98.3%, respectively (P = .22). There were no differences among the groups in proportions of pediatric patients (P = .55) or multiple intubation attempts (P = .83). Use of paralytic agents was more frequent in ground and in-flight groups as compared with hospital group patients (P = .03). We conclude that with the aircraft and aeromedical crew studied, ETI was as likely to be successful in-flight as in other settings.