# Computer reservation system

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.
Airline reservations systems may be integrated into a larger passenger service system, which also includes an airline inventory system and a departure control system. The current centralised reservation systems are vulnerable to network-wide system disruptions.

## History
### MARS-1

The MARS-1 train ticket reservation system was designed and planned in the 1950s by the Japanese National Railways' R&D Institute, now the Railway Technical Research Institute, with the system eventually being produced by Hitachi in 1958. It was the world's first seat reservation system for trains. The MARS-1 was capable of reserving seat positions, and was controlled by a transistor computer with a central processing unit and a 400,000-bit magnetic drum memory unit to hold seating files. It used many registers, to indicate whether seats in a train were vacant or reserved to accelerate searches of and updates to seat patterns, for communications with terminals, printing reservation notices, and CRT displays.

### Remote access

In 1953 Trans-Canada Airlines (TCA) started investigating a computer-based system with remote terminals, testing one design on the University of Toronto's Ferranti Mark 1 machine that summer. Though successful, the researchers found that input and output was a major problem. Ferranti Canada became involved in the project and suggested a new system using punched cards and a transistorized computer in place of the unreliable tube-based Mark I. The resulting system, ReserVec, started operation in 1962, and took over all booking operations in January 1963. Terminals were placed in all of TCA's ticketing offices, allowing all queries and bookings to complete in about one second with no remote operators needed.
In 1953 American Airlines CEO C. R. Smith chanced to sit next to R. Blair Smith, a senior IBM sales representative, on a flight from Los Angeles to New York. C.R. invited Blair to visit their Reservisor system and look for ways that IBM could improve the system. Blair alerted Thomas Watson Jr. that American was interested in a major collaboration, and a series of low-level studies started. Their idea of an automated airline reservation system (ARS) resulted in a 1959 venture known as the Semi-Automatic Business Research Environment (SABRE), launched the following year. By the time the network was completed in December 1964, it was the largest civil data processing system in the world.
Other airlines established their own systems. Pan Am launched its PANAMAC system in 1964. Delta Air Lines launched the Delta Automated Travel Account System (DATAS) in 1968. United Airlines and Trans World Airlines followed in 1971 with the Apollo Reservation System and Programmed Airline Reservation System (PARS), respectively. Soon, travel agents began pushing for a system that could automate their side of the process by accessing the various ARSes directly to make reservations. Fearful this would place too much power in the hands of agents, American Airlines executive Robert Crandall proposed creating an industry-wide computer reservation system to be a central clearing house for U.S. travel; other airlines demurred, citing fear that United States antitrust law may have been breached.

### Travel agent access

In 1976, United Airlines began offering its Apollo system to travel agents; while it would not allow the agents to book tickets on United's competitors, the marketing value of the convenient terminal proved indispensable. SABRE, PARS, and DATAS were soon released to travel agents as well. Following airline deregulation in 1978, an efficient CRS proved particularly important; by some counts, Texas Air executive Frank Lorenzo purchased money-losing Eastern Air Lines specifically to gain control of its SystemOne CRS.
Also in 1976 Videcom international with British Airways, British Caledonian and CCL launched Travicom, the world's first multi-access reservations system (wholly based on Videcom technology), forming a network providing distribution for initially two and subsequently 49 subscribing international airlines (including British Airways, British Caledonian, Trans World Airlines, Pan Am, Qantas, Singapore Airlines, Air France, Lufthansa, Scandinavian Airlines System, Air Canada, KLM, Alitalia, Cathay Pacific and Japan Airlines) to thousands of travel agents in the UK. It allowed agents and airlines to communicate via a common distribution language and network, handling 97% of UK airline business trade bookings by 1987. The system went on to be replicated by Videcom in other areas of the world including the Middle East (DMARS), New Zealand, Kuwait (KMARS), Ireland, Caribbean, United States and Hong Kong. Travicom was a trading name for Travel Automation Services Ltd. When British Airways (who by then owned 100% of Travel Automation Services Ltd) chose to participate in the development of the Galileo system Travicom changed its trading name to Galileo UK and a migration process was put in place to move agencies from Travicom to Galileo.
European airlines also began to invest in the field in the 1980s initially by deploying their own reservation systems in their homeland, propelled by growth in demand for travel as well as technological advances which allowed GDSes to offer ever-increasing services and searching power. In 1987, a consortium led by Air France and West Germany's Lufthansa developed Amadeus, modeled on SystemOne. Amadeus Global Travel Distribution was launched in 1992. In 1990, Delta, Northwest Airlines, and Trans World Airlines formed Worldspan, and in 1993, another consortium (including British Airways, KLM, and United Airlines, among others) formed the competing company Galileo GDS based on Apollo. Numerous smaller companies such as KIU have also formed, aimed at niche markets not catered for by the four largest networks, including the low-cost carrier segment, and small and medium size domestic and regional airlines.

## Trends

For many years, global distribution systems (GDSs) have had a dominant position in the travel industry. To bypass the GDSs, and avoid high GDS fees, airlines have started to sell flights directly through their websites. Another way to bypass the GDSs is direct connection to travel agencies, such as that of American Airlines.

## Major airline CRS systems

| Name | Created by | Airlines using | Also used by |
| AirCore | Unisys | GDS and other PSS systems, Low Cost Airlines, Full Services Carriers, Hybrid Airlines | Several large corporations |
| Abacus (purchased by Sabre in 2015) | All Nippon Airways Cathay Pacific China Airlines EVA Airways Garuda Indonesia Malaysia Airlines Philippine Airlines Royal Brunei Airlines SABRE Singapore Airlines | | Online travel agencies Over 450 individual airlines Over 25 countries in Asia Pacific Over 80,000 hotels |
| ACCELaero | ISA, Information Systems Associates FZE | Air Arabia Kam Air Mahan Air Zest Air Over 14 airlines including low-cost carriers and full-service carriers | |
| Amadeus (1987) | Air France Iberia Airlines Lufthansa Scandinavian Airlines System | All Nippon Airways Aegean Airlines Air India Air Canada Air Algérie Air Astana Air Caraïbes Air Corsica Air Côte d'Ivoire Air Dolomiti Air France Air Greenland Air Mauritius Air Serbia Air Tahiti Nui Air Vanuatu airBaltic Aircalin Asiana Airlines Austrian Airlines Avianca Bangkok Airways Binter Canarias British Airways Brussels Airlines Bulgaria Air Camair-Co CapeAir Cathay Pacific China Airlines Cimber Sterling Corsair Croatia Airlines Czech Airlines EgyptAir El Al Etihad Airways EVA Airways Fiji Airways Finnair Flybe Garuda Indonesia Hawaiian Airlines Hunnu Air Iberia Icelandair Japan Airlines KLM Kenya Airways Korean Air Kuwait Airways LACSA Libyan Airlines LOT Lufthansa Malaysia Airlines MIAT Mongolian Airlines Middle East Airlines OpenSkies Philippine Airlines Qantas Qatar Airways Rossiya Royal Air Maroc Royal Brunei Airlines Royal Jordanian Ukrainian International Airlines S7 Airlines Safi Airways SATA Air Açores SATA International Saudia Scandinavian Airlines Seaport Airlines Singapore Airlines South African Airways Southwest Airlines SriLankan Airlines Starlux Airlines Swiss International Air Lines TACA Airlines TAM Airlines TAM Mercosur TAP Portugal Thai Airways Thai Smile Thai Vietjet Air (soon) Toumaï Air Tchad Trans Air Congo Tunisair Turkish Twin Jet VietJet Air (soon) Uni Air Ural Airlines Widerøe | 144 Airline Passenger Service System customers through 60,000 airline sales offices worldwide 90,000 travel agencies worldwide, both offline and online, in 195 countries. Online agencies include: Yatra.com MakeMyTrip Expedia ebookers CheapTickets Opodo Jetabroad 440 bookable airlines (including over 60 Low Cost Carriers) Over 100,000 unique hotel properties 30 Car rental companies representing over 36,000 car rental locations 21 Cruise Lines 203 Tour Operators 103 Rail Operators 23 Travel Insurance Companies |
| ameliaRES | InteliSys Aviation Systems | Over 40 low-cost carriers and regional airlines* VietJet Air Thai VietJet Air Air Borealis Air Liaison Air Saint-Pierre Air Timor Bearskin Airlines Calm Air Central Mountain Air Cronos Airlines DAC Aviation International Flair Airlines Int'Air Iles Lao Skyway Pacific Coastal Airlines PAL Airlines Pascan Aviation Perimeter Aviation SKS Airways SkyTrans Airlines Surinam Airways Tailwind Aviation VI Air Link Thai Platinum International Airlines Vieques Air Link Wasaya Airways LP Wildcat Touring Wilderness Seaplanes |
| Avantik PSS | Bravo Passenger Solutions | Alliance Airlines Aurginy Bassaka Air Cobham Edelweiss Air La Compagnie Peach People's Sky Express Susi Air Tara Air Tassili Airlines Yeti Airlines | Online Travel Agencies |
| Axess | | Japan Airlines | |
| Deltamatic (PSS) | Delta Air Lines | Delta Air Lines Virgin Atlantic | |
| Crane | Hitit | Aero Contractors Air Manas Air Mediterranean Air Namibia Air Tuerk APG Airlines Arik Air Bahamas Air Chalair Euro Airlines Kamair Nesma Airlines Passion Air Pakistan International Airlines Pegasus Airlines Precision Air Turkmenistan Airlines Nouvel Air Air Tanzania K2 Airlines FlyArystan Uganda Airlines OneSky Blue Stream Libyan Wings Sky Mali Win Air Animawings Air Seychelles Contour Airlines Yemenia Airways Nella Linhas Aeros Mai Air Air KBZ Daallo Cabo Verde Royal Brunei Airlines | |
| Internet Booking Engine | Mercator | Qatar Airways Sri Lankan Airlines SAS Braathens | Over 3 individual airlines |
| KIU | | Air Cuenca EasyFly Guinea Líneas Aéreas LASER Airlines LC Busre Línea Aérea Amaszonas MAYAir SAEREO Sol América Star Perú Tiara Air Transportes Aéreos Cielos Andinos ValueJet Venezolana | Over 20 individual airlines Over 10 countries in Latin America, North America, Africa and Europe Travel agencies and wholesale tour operators worldwide |
| MARS | Railway Technical Research Institute Hitachi | | Japan Railways Group Japanese travel agencies |
| Mercator | Emirates | Air Malawi Air Tanzania Air Zimbabwe CTK – CiTylinK Danube Wings Emirates flydubai InterSky Merpati Nusantara Airlines People's Sky Work Airlines Surinam Airways Syrian Air Yemenia Zest Airways | |
| New Skies | Navitaire | AeroItalia AirAsia AirAsia Cambodia AirAsia X Air India Express Air Premia Akasa Air Allegiant Air Azul Blue Air Breeze Airways Buzz Cebu Pacific Citilink Eastar Jet Eurowings Eurowings Europe Firefly Flynas FlyOne FlyOne Armenia Frontier Airlines HK Express IndiGo Indonesia AirAsia Jambojet Jazeera Airways Jeju Air JetSmart JetSmart Argentina JetSmart Colombia JetSmart Perú Jetstar Jetstar Asia Jetstar Japan JSX Lauda Europe Malta Air Norse Atlantic Airways Norse Atlantic UK Philippines AirAsia Pobeda Porter Airlines Ryanair Ryanair UK Scoot SpiceJet Spirit Airlines Sun Country Tigerair Taiwan Transavia Transavia France TUI Airways TUI fly Belgium TUI fly Deutschland TUI fly Netherlands TUI fly Nordic Thai AirAsia Thai AirAsia X Viva Volaris Volaris Costa Rica Volaris El Salvador Volotea Vueling Wizz Air Wizz Air Abu Dhabi Wizz Air Malta Wizz Air UK | |
| PARS/SHARES by EDS | | Air Nigeria Braniff International Airways COPA Airlines Hawaii Island Air United Airlines | |
| Patheo | Finnair KLM Lufthansa | | Online travel agencies including Airgorrila American Express Anyfares Flights |
| Radixx | | Aerocon Africa World Airlines Air India Express Air Rarotonga Air Transat Air Turks & Caicos Eznis Federal Air Fly Dubai Freedom Air Guam Great Lakes Aviation Gryphon JetUs Lydd Air Mokulele Nature Air Nok Air Polynesian Primera Air Rotana Jet Syphax Airlines Transat Tours Wingo | |
| Sabre (1960) | American Airlines | Aeroflot Aerolíneas Argentinas Aeroméxico Air Malta Air New Zealand Air Serbia Alaska Airlines American Airlines Avior Airlines Bahamasair Bearskin Airlines Canadian North Central Mountain Air COPA Airlines Cyprus Airways Ethiopian Airlines First Air Gol Linhas Aéreas Inteligentes Gulf Air JetBlue LATAM Airlines LATAM Ecuador LATAM Perú Oman Air Pakistan International Airlines RavnAir Group SBA Airlines TRIP Linhas Aéreas Vietnam Airlines Virgin Australia WestJet | Online Travel Agencies: Travelocity Lastminute.com Travel Guru Priceline Schedules for 400 airlines 380 airline industry customers, including 44 airlines representing all major alliances 88,000 hotels 50 rail carriers 180 tour operators 13 cruise lines 24 car rental brands serving 30,000 locations 9 limousine vendors providing access to more than 33,500 ground service providers 55,000 travel agencies in over 100 countries |
| Sell-More-Seats | WorldTicket | More than 55 scheduled carriers, charter carriers and low-cost carriers in Europe, Africa, Asia, Middle East and Central America | |
| SkyVantage Airline Software | | ABM Air Africa's Connection Air Century Air Unlimited Branson AirExpress Caicos Express Airlines Caribbean Helicopters Denver Air One Caribbean Pacificair Sansa Sky Bahamas Sunshine Coast Air Watermakers Air Western Air | |
| Travel Technology Interactive | Travel Technology Interactive Group | Over 40 low-cost carriers, regional airlines and Legacy carriers of which Air Antilles Express Air KBZ Europe Airpost Ewa Air Jubba Airways Our Airline Passaredo Linhas Aéreas SATENA Zanair | Travel agencies and wholesale tour operators worldwide |
| TravelSky | | Air China Air Macau China Eastern Airlines China Southern Airlines Hainan Airlines Hong Kong Airlines Shandong Airlines Shanghai Airlines Sichuan Airlines Air Manas | Online travel agencies including Ctrip eLong mangocity |
| Travelport GDS Includes Apollo (1971), Galileo (1987) and Worldspan (1990) | Apollo: United Airlines. Galileo: British Airways, KLM, Alitalia, Swissair, Austrian Airlines, Olympic Airways, Sabena, TAP Air Portugal, Aer Lingus. Worldspan: Delta Air Lines, Northwest Airlines (Northwest Airlines merged with Delta Air Lines which uses Deltamatic), Trans World Airlines (merged with American Airlines which currently uses Sabre). | | Zuji BookIt.com ebookers Expedia Flight Centre Hotels Hotwire Orbitz Priceline Trailfinders Webjet Travel Agencies Online Travel Services Airlines Corporations |

## Other systems

* Polyot-Sirena