Q. Carrier Regions in Airline Data
Carrier regions (Domestic, Atlantic, Latin American, Pacific and International) are defined in 14 CFR 241.21:
(g) Four separate air carrier entities shall be established for large certificated air carriers conducting scheduled service for the purpose of submitting the prescribed reports. They are as follows: (1) Domestic operations; (2) operations via the Atlantic Ocean; (3) operations via the Pacific Ocean; and (4) operations in Latin American areas. With respect to the first classification, the domestic entity shall embrace all operations within and between the 50 States of the United States, the District of Columbia, the Commonwealth of Puerto Rico and the U.S. Virgin Islands, and shall also include Canadian transborder operations. The reports to be submitted by each entity shall be comparable to those required of a distinct legal entity whether the reporting entity constitutes such an entity, a semiautonomous physically separated operating division of the carrier, or an entity established for reporting purposes only.
(h) Two separate entities shall be established for large certificated air carriers predominantly engaged in conducting charter activities for the purpose of submitting the prescribed reports: (1) Domestic operations; and (2) International operations. The domestic entity includes all operations within and between the 50 States of the United States, the District of Columbia, the Commonwealth of Puerto Rico, and the U.S. Virgin Islands. All other operations will be in the international entity.
Foreign carriers can only file under one region (International) and do not break out their services by region. Only US certificated air carriers report separate geographic entities.
The attached document (which includes a map) may also be of assistance.