Airline reservations system

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Airline reservation systems (ARS) are systems that allow an airline to sell their inventory (seats). It contains information on schedules and fares and contains a database of reservations (or passenger name records) and of tickets issued (if applicable). ARSs are part of passenger service systems (PSS), which are applications supporting the direct contact with the passenger.


ARS eventually evolved into the computer reservations system (CRS). A computer reservation system is used for the reservations of a particular airline and interfaces with a global distribution system (GDS) which supports travel agencies and other distribution channels in making reservations for most major airlines in a single system.


Airline reservation systems incorporate airline schedules, fare tariffs, passenger reservations and ticket records. An airline's direct distribution works within their own reservation system, as well as pushing out information to the GDS. The second type of direct distribution channel are consumers who use the internet or mobile applications to make their own reservations. Travel agencies and other indirect distribution channels access the same GDS as those accessed by the airline reservation systems, and all messaging is transmitted by a standardized messaging system that functions on two types of messaging that transmit on SITA's high level network (HLN). These messaging types are called Type A [usually EDIFACT format] for real time interactive communication and Type B [TTY] for informational and booking type of messages. Message construction standards set by IATA and ICAO, are global, and apply to more than air transportation. Since airline reservation systems are business critical applications, and they are functionally quite complex, the operation of an in-house airline reservation system is relatively expensive.

Prior to deregulation, airlines owned their own reservation systems with travel agents subscribing to them. Today, the GDS are run by independent companies with airlines and travel agencies being major subscribers.

As of February 2009, there are only four major GDS providers in the market: Amadeus, Travelport (which operates the Apollo, Worldspan and Galileo systems), Sabre and Shares. There is one major Regional GDS, Abacus, serving the Asian market and a number of regional players serving single countries, including Travelsky (China), Infini and Axess (both Japan) and Topas (South Korea). Of these, Infini is hosted within the Sabre complex, Axess is in the process of moving into a partition within the Worldspan complex, and Topas agencies will be migrating into Amadeus.

Reservation systems may host "ticket-less" airlines and "hybrid" airlines that use e-ticketing in addition to ticket-less to accommodate code-shares and interlines.

In addition to these "standardized" GDS, some airlines have proprietary versions which they use to run their flight operations. A few examples are Delta's OSS and Deltamatic systems and EDS SHARES. SITA Reservations remains the largest neutral multi-host airline reservations system, with over 100 airlines currently managing inventory.

Inventory management

In the airline industry, available seats are commonly referred to as inventory. The inventory of an airline is generally classified into service classes (e.g. economy, premium economy, business or first class) and any number of fare classes, to which different prices and booking conditions may apply. Fare classes are complicated and vary from airline to airline, often indicated by a one letter code. The meaning of these codes are not often known by the passenger, but conveys information to airline staff, for example they may indicate that a ticket was fully paid, or discounted or purchased through a loyalty scheme, etc. Some seats may not be available for open sale, but reserved for example for connecting flight or loyalty scheme passengers. Overbooking is also a common practice, and is an exception to inventory management principles. One of the core functions of inventory management is inventory control. Inventory control monitors how many seats are available in the different fare classes, and by opening and closing individual fare classes for sale.

A flight schedule management system forms the foundation of the inventory management system. Besides other functions, it is critical for ticket sales, crew member assignments, aircraft maintenance, airport coordination, and connections to partner airlines. The schedule system monitors what and when aircraft will be available on particular routes, and their internal configuration. Inventory data is imported and maintained from the schedule distribution system. Changes to aircraft availability would immediately impact the available seats of the fleet, as well as the seats which had been sold.

The price for each sold seat is determined by a combination of the fares and booking conditions stored in the Fare Quote System,. In most cases, inventory control has a real time interface to an airline’s yield management system to support a permanent optimization of the offered booking classes in response to changes in demand or pricing strategies of competitors.

Availability display and reservation (PNR)

Users access an airline’s inventory through an availability display. It contains all offered flights for a particular city-pair with their available seats in the different booking classes. This display contains flights which are operated by the airline itself as well as code share flights which are operated in co-operation with another airline. If the city pair is not one on which the airline offers service, it may display a connection using its own flights or display the flights of other airlines. The availability of seats of other airlines is updated through standard industry interfaces. Depending on the type of co-operation, it supports access to the last seat (last seat availability) in real-time. Reservations for individual passengers or groups are stored in a so-called passenger name record (PNR). Among other data, the PNR contains personal information such as name, contact information or special services requests (SSRs) e.g. for a vegetarian meal, as well as the flights (segments) and issued tickets. Some reservation systems also allow to store customer data in profiles to avoid data re-entry each time a new reservation is made for a known passenger. In addition, most systems have interfaces to CRM systems or customer loyalty applications (aka frequent traveler systems). Before a flight departs, the so-called passenger name list (PNL) is handed over to the departure control system that is used to check-in passengers and baggage. Reservation data such as the number of booked passengers and special service requests is also transferred to flight operations systems, crew management and catering systems. Once a flight has departed, the reservation system is updated with a list of the checked-in passengers (e.g. passengers who had a reservation but did not check in (no shows) and passengers who checked in, but did not have a reservation (go shows)). Finally, data needed for revenue accounting and reporting is handed over to administrative systems.

Fare quote and ticketing

List of fares for travel on Delta Air Lines from San Francisco, CA to Boston, MA. Applicable booking classes, as well as specific restrictions such as minimum stay and advance purchase can be seen. Airline Fare Chart.png
List of fares for travel on Delta Air Lines from San Francisco, CA to Boston, MA. Applicable booking classes, as well as specific restrictions such as minimum stay and advance purchase can be seen.

The Fares data store contains fare tariffs, rule sets, routing maps, class of service tables, and some tax information that construct the price – "the fare". Rules like booking conditions (e.g. minimum stay, advance purchase, etc.) are tailored differently between different city pairs or zones, and assigned a class of service corresponding to its appropriate inventory bucket. Inventory control can also be manipulated manually through the availability feeds, dynamically controlling how many seats are offered for a particular price by opening and closing particular classes.

The compiled set of fare conditions is called a fare basis code. There are two systems set up for the interchange of fares data ATPCO and SITA, plus some system to system direct connects. This system distributes the fare tariffs and rule sets to all GDSs and other subscribers. Every airline employs staff who code air fare rules in accordance with yield management intent. There are also revenue managers who watch fares as they are filed into the public tariffs and make competitive recommendations. Inventory control is typically manipulated from here, using availability feeds to open and close classes of service.

The role of the ticketing complex is to issue and store electronic ticket records and the very small number of paper tickets that are still issued. Miscellaneous charges order (MCO) is still a paper document; IATA has working groups defining the replacement document the electronic multipurpose document (EMD) as at 2010. The electronic ticket information is stored in a database containing the data that historically was printed on a paper ticket including items such as the ticket number, the fare and tax components of the ticket price or exchange rate information. In the past, airlines issued paper tickets; since 2008, IATA has been supporting a resolution to move to 100% electronic ticketing. So far, the industry has not been able to comply due to various technological and international limitations. The industry is at 98% electronic ticket issuance today, although electronic processing for MCOs was not available in time for the IATA mandate.

Notable systems

ACCELaeroPSS, reservations, DCS, inventory and e-commerce platform. Information Systems Associates FZE
AirCore Passenger services system (PSS) of modular, open-platform, web applications that replace core legacy systems. [1] Unisys
Altéa ResIntegrated airline reservation system and global distribution system (GDS). Amadeus IT Group
Crane PAXWeb-based airline reservations and ticketing system. Hitit Computer Services
Navitaire New Skies Integrated Customer Centric Passenger Service SystemIntegrated reservations, departure control, inventory system and e-commerce platform. Navitaire
Radixx International Hybrid travel distribution and PSS.
SabreSonic Customer Sales & ServiceIntegrated reservations, departure control, inventory system and e-commerce platform. Sabre Airline Solutions
SITA Horizon Customer Sales & ServiceIntegrated reservations, departure control, inventory system and e-commerce platform. SITA
Travel Technology Interactive SolutionsIntegrated airline management system and global distribution system (GDS). Travel Technology Interactive
Videcom Reservations System (VRS)GDS, IET, Codeshare. Videcom international


Agent set of the Magnetronic Reservisor system Magnetronic Reservisor.jpg
Agent set of the Magnetronic Reservisor system

Until the 1950s, airline reservations used manual systems at centralized reservation centers, which consisted of groups of people in a room with physical cards that represented inventory, in this case, seats on airplanes. In the late 1950s, American Airlines wanted a system that would allow real-time access to flight details in all of its offices, and the integration and automation of its booking and ticketing processes. It introduced an electronic reservations system, Magnetronic Reservisor, in 1952. [2] In 1964, it developed the Sabre (Semi-Automated Business Research Environment). [3] Sabre's breakthrough was its ability to keep inventory correct in real time, accessible to agents around the world.

The deregulation of the airline industry, in the Airline Deregulation Act, meant that airlines, which had previously operated under government-set fares ensuring airlines at least broke even, now needed to improve efficiency to compete in a free market. In this deregulated environment, the ARS and its descendants became vital to the travel industry.

See also

Further reading

Related Research Articles

International Air Transport Association International trade association for airlines

The International Air Transport Association is a trade association of the world's airlines founded in 1945. IATA has been described as a cartel since, in addition to setting technical standards for airlines, IATA also organized tariff conferences that served as a forum for price fixing.

Codeshare agreement

A codeshare agreement, also known as codeshare, is a business arrangement, common in the aviation industry, in which two or more airlines publish and market the same flight under their own airline designator and flight number as part of their published timetable or schedule. Typically, a flight is operated by one airline while seats are sold for the flight by all cooperating airlines using their own designator and flight number.

Yield management is a variable pricing strategy, based on understanding, anticipating and influencing consumer behavior in order to maximize revenue or profits from a fixed, time-limited resource. As a specific, inventory-focused branch of revenue management, yield management involves strategic control of inventory to sell the right product to the right customer at the right time for the right price. This process can result in price discrimination, in which customers consuming identical goods or services are charged different prices. Yield management is a large revenue generator for several major industries; Robert Crandall, former Chairman and CEO of American Airlines, gave yield management its name and has called it "the single most important technical development in transportation management since we entered deregulation."

Computer reservation systems, or central reservation systems (CRS), are computerized systems used to store and retrieve information and conduct transactions related to air travel, hotels, car rental, or other activities. Originally designed and operated by airlines, CRSs were later extended for use by travel agencies, and global distribution systems (GDSs) to book and sell tickets for multiple airlines. Most airlines have outsourced their CRSs to GDS companies, which also enable consumer access through Internet gateways. Modern GDSs typically also allow users to book hotel rooms, rental cars, airline tickets as well as other activities and tours. They also provide access to railway reservations and bus reservations in some markets, although these are not always integrated with the main system. These are also used to relay computerized information for users in the hotel industry, making reservation and ensuring that the hotel is not overbooked.

Sabre Global Distribution System, owned by Sabre Corporation, is used by travel agents and companies around the world to search, price, book, and ticket travel services provided by airlines, hotels, car rental companies, rail providers and tour operators. Sabre aggregates airlines, hotels, online and offline travel agents and travel buyers.

A passenger name record (PNR) is a record in the database of a computer reservation system (CRS) that contains the itinerary for a passenger or a group of passengers travelling together. The concept of a PNR was first introduced by airlines that needed to exchange reservation information in case passengers required flights of multiple airlines to reach their destination (“interlining”). For this purpose, IATA and ATA have defined standards for interline messaging of PNR and other data through the "ATA/IATA Reservations Interline Message Procedures - Passenger" (AIRIMP). There is no general industry standard for the layout and content of a PNR. In practice, each CRS or hosting system has its own proprietary standards, although common industry needs, including the need to map PNR data easily to AIRIMP messages, has resulted in many general similarities in data content and format between all of the major systems.

SITA (company)

SITA is a multinational information technology company providing IT and telecommunication services to the air transport industry. The company provides its services to around 400 members and 2,800 customers worldwide, which it claims is about 90% of the world's airline business. Around the world, nearly every passenger flight relies on SITA technology.

ReserVec was a computerized reservation system developed by Ferranti Canada for Trans-Canada Airlines in the late 1950s. It appears to be the first such system ever developed, predating the more famous SABRE system in the US by about two years. Although Ferranti had high hopes that the system would be used by other airlines, no further sales were forthcoming and development of the system ended. Major portions of the transistor-based circuit design were put to good use in the Ferranti-Packard 6000 computer, which would later go on to see major sales in Europe as the ICT 1904.

Amadeus IT Group Spanish travel technology company

Amadeus IT Group, S.A. is a major Spanish IT provider for the global travel and tourism industry.

Global distribution system

A global distribution system (GDS) is a computerised network system owned or operated by a company that enables transactions between travel industry service providers, mainly airlines, hotels, car rental companies, and travel agencies. The GDS mainly uses real-time inventory to service providers. Travel agencies traditionally relied on GDS for services, products and rates in order to provide travel-related services to the end consumers. Thus, a GDS can link services, rates and bookings consolidating products and services across all three travel sectors: i.e., airline reservations, hotel reservations, car rentals.


The Airline Tariff Publishing Company is a privately held corporation that engages in the collection and distribution of fare and fare-related data for the airline and travel industry. ATPCO currently works with more than 427 airlines worldwide, and it supplies more than 99% of the industry’s intermediated fare data to all the major airfare pricing engines, storing over 211 million active fares in its database.

Airline ticket Entrance ticket used for air travel

An airline ticket is a document or electronic record, issued by an airline or a travel agency, that confirms that an individual is entitled to a seat on a flight on an aircraft. The airline ticket may be one of two types: a paper ticket, which comprises coupons or vouchers; and an electronic ticket.

Videcom International Limited is a United Kingdom travel technology company based in Henley-on-Thames. It designs, develops and provides modern computer reservations systems to airlines and the travel industry, specializing in the hosting and distribution of airline sales.

Alternate air ticket purchasing order systems allow for alternative ways of purchasing air tickets and GDS Connectivity not involving Internet or personal TA contact.

A fare basis code is an alphabetic or alpha-numeric code used by airlines to identify a fare type and allow airline staff and travel agents to find the rules applicable to that fare. Although airlines now set their own fare basis codes, there are some patterns that have evolved over the years and may still be in use.

A passenger service system (PSS) is a series of critical systems used by airlines. The PSS usually comprises an airline reservations system, an airline inventory system and a departure control system (DCS).

The Electronic Miscellaneous Document (EMD) is an International Air Transport Association (IATA) standard for electronically documenting ancillary revenue; that is, all other sales and transactions between airlines and passengers besides electronic tickets. It is a step toward moving the airline industry to purely electronic transactions in the business-to-consumer context.

Navitaire LLC is a transportation industry technology services subsidiary of multinational IT Provider for the global travel and tourism industry Amadeus IT Group. Navitaire primarily offers systems for passenger reservations, travel commerce, ancillary revenue and merchandising, as well as revenue accounting and revenue management to airlines and rail companies.

E-kvytok - is the first online operator in Ukraine that made it possible to purchase train tickets. It was created by the state enterprise AT "Ukrainian Railways" JSC.

An airfare is the fee paid by a passenger for air transport and is made up of the charge for a passenger to fly from an origin to destination and includes the conditions, rules and restrictions for travelling on the airfare.


Airline reservation system: All you need to know

  2. "Magnetronic Reservisor". American Airlines C.R. Smith Museum. Retrieved 3 August 2014. The Magnetronic Reservisor, introduced in 1952, was the first electronic reservations system in the airline industry
  3. "Sabre The First Online Reservation System". IBM. Retrieved 16 April 2020.