The three main international GDSs are Amadeus, Sabre and Travelport. Travelport’s system is now called Travelport+ (formerly Galileo), and it still runs the older Apollo and Worldspan systems for some customers. Alongside airline seats, GDSs carry hotels, car hire and rail. Travel agencies connect to them as subscribers, and booking engines and mid-office systems often connect to one or more of them.

How it works for an agent

A GDS is the traditional route to scheduled airline fares, including private and negotiated fares, and to creating and servicing flight bookings. For example, an agent books a London to Singapore return in a GDS, which creates the booking record, or PNR. An IATA-accredited agent can then issue the ticket and settle through IATA’s Billing and Settlement Plan.

Common confusion

• A GDS is not a booking engine or a website. It is the business-to-business network behind them.

• With IATA’s New Distribution Capability, some airline fares and extras are now sold outside traditional GDS connections, and some airlines have charged extra for GDS bookings. All three GDSs now also carry NDC content.

• UK law does not define “GDS”. The CRS Regulation (EC) No 80/2009, which still applies in the UK, uses the term computerised reservation system (CRS) instead.