Skip to main content

Glossary for the airline industry

From A-Z, this glossary covers definitions and explanations for common airline industry terminology.


A set of fields in the Fare Manager Rules system for Combinations (Category 10) that provides access to and a summary of subcategory data.


Sales Data Exchange

second freedom

The right to make a technical landing for refueling, etc. without boarding or disembarking revenue traffic.

secondary passenger

The Secondary Passenger Type Code is used to indicate the PTCs that may be further discounted by the presence of Categories 19-22 in the actual Fare By Rule tariff.

secondary portion of travel

A portion of travel of a fare component that is not determined as primary portion of travel.


In international fares, a portion of a journey covered by a single flight coupon. Also called segment.


In domestic US/CA fares, a portion of a journey covered by a single flight coupon. Also called sector.

Selling fare amount

The amount a passenger pays the agency (or consolidator) for the Negotiated Fare. Also called the Selling amount.

Selling updater

The person or organization who may update the Selling fare based on the Net fare and who makes the Negotiated Fare available for travel agents.


A continuous or related series. Mainly used in reference to the organization of data with categories in the FareManager Rules system.

Service Fees

ATPCO's suite of products that automates and centralizes the collection of ancillary fees for a wide range of secondary charges and services. The current suite of products includes Carrier-Imposed Fees, Ticketing Fees, Optional Services (including baggage allowance and charges), and Branded Fares.

Service Type Code

A code identifying the service for which a fee will be assessed. This code consists of a generic service code and a more specific Sub Code to further define the service. Optional Services uses the following six service types: flight-related service, ticket-related services, fare-related services, baggage allowance, baggage charges, and merchandise.

servicing an order

The act of processing changes to an order, such as postponing a trip or requesting a refund after the offer has been purchased. It can be initiated by either the passenger (voluntary) or the airline (involuntary).


The process by which interline partners allocate revenue on a ticket where each carrier operated a portion of the journey. These portions are determined by flight coupon.

sideline city

The city that appears second in a market city pair. Also called destination city.


Sale inside, ticketing inside; sold and ticketed in country of journey origin


Sale inside, ticketing outside; sold in country of journey origin and ticketed outside country of origin.

sixth freedom

The right to carry revenue traffic between two points within a foreign country.


Sale outside, ticketing inside; sold outside country of journey origin and ticketed inside country of origin.


Sale outside, ticketing outside; sold and ticketed outside country of journey origin.