1. The carrier whose baggage rules will apply on journeys.
2. For journeys that are required to follow DOT reservations, it is the first most significant marketing carrier on the journey, as determined by these conditions, and charges for these journeys are applied per direction:
   a. For travel between two or more Tariff Conference areas, the carrier performing carriage on the first sector on the passenger's journey that crosses from one area to another. Exception: TC123 only, the carrier providing carriage on the first sector on the passenger's journey that crosses between TC1 and TC2.
   b. For travel between Tariff Conference sub-areas, the carrier performing carriage on the first sector on the passenger's journey that crosses from one sub-area to another.
   c. For travel within a Tariff Conference sub-area, the carrier performing carriage on the first international sector on the passenger's journey.
3. For all other journeys, it is the most significant operating carrier for each checked portion, and charges for these journeys are applied per checked portion:
   a. For travel between two or more Tariff Conference areas, the carrier performing carriage on the first sector on the checked portion that crosses from one area to another. Exception: TC123 only, the carrier providing carriage on the first sector on the checked portion that crosses between TC1 and TC2.
   b. For travel between Tariff Conference sub-areas, the carrier performing carriage on the first sector on the checked portion that crosses from one sub-area to another.
   c. For travel within a Tariff Conference sub-area, the carrier performing carriage on the first international sector on the checked portion.
   d. For travel within a single country, the first carrier on the checked portion.

Maximum permitted mileage.

A service of transportation with a single flight number making two or more intermediate stops.

An agreement between three or more trading partners to either send data or process data in a specified manner.