RotorPedia’s Aircraft & Base Data provides information on Helicopter Emergency Medical Services (HEMS) and Helicopter Air Ambulance (HAA) programs throughout the northeastern United States. The database includes aircraft assignments, base locations, registration and serial numbers, year of manufacture, aircraft manufacturers and models, and operating vendors.

To simplify data maintenance and account for frequently changing aircraft and base assignments, some programs—such as the Maryland State Police Aviation Command—are listed in numerical order rather than by base location.