GDS vs NDC: how business travel is booked, and the UK rules on reservation systems

A travel management company books most flights through a global distribution system (GDS): one system holding the schedules, seats and fares of many airlines. NDC — IATA’s New Distribution Capability — is something different: a data standard that lets an airline build and send its own offers, through a GDS or directly. In UK law a GDS is a “computerised reservation system”, and a code of conduct that began as EU law still governs how it displays flights and handles booking data here. This page sets out the definitions from the regulation and from IATA, and what they mean for a company buying travel.

GDS and NDC side by side

The first row is the one that clears up most confusion. A GDS is a place content is held and searched. NDC is a format for airline content. So “GDS or NDC” is not quite the right choice to put to a supplier; the real questions are which airline content they can see, through which connections, and on what screen.

What a GDS is, in UK law

The law does not use the word “GDS”. It uses “computerised reservation system”, and it defines it:

The company that runs one is the “system vendor”: “‘system vendor’ means any entity and its affiliates which is or are responsible for the operation or marketing of a CRS;” The travel agency or TMC that uses it is a “subscriber”: “a person or an undertaking, other than a participating carrier, using a CRS under contract with a system vendor with the purpose of making reservations of air-transport and related products on behalf of a client”. And the scope is set in Article 1:

This is retained law: legislation.gov.uk notes that the words in Article 1 were substituted on 31 December 2020 by the Computer Reservation Systems (Amendment) (EU Exit) Regulations 2018 (S.I. 2018/1080). Even “fares” is defined, and the definition reaches into agency pay: fares include “remuneration and conditions offered to agency and other auxiliary services”.

The four rules that matter to a buyer

1. The display must be neutral

For a company buying travel, this is a real protection. A consultant working on a GDS screen is looking at a display the law says cannot be ordered by who the airline is. What the consultant then recommends is a matter for your travel policy and your supplier’s terms — not for the display.

2. Data about the agency is anonymised

System vendors may make marketing, booking and sales data (“MIDT”) available to airlines. Article 7 limits it: such data “they shall include no identification either directly or indirectly of that subscriber unless the subscriber and the system vendor agree on the conditions for the appropriate use of such data.” And “Participating carriers shall not use such data in order to influence the choice of the subscriber.”

3. No exclusivity

A system vendor may not “make it a condition of participation in its CRS that a participating carrier may not at the same time be a participant in another system or that a participating carrier may not freely use alternative reservation systems such as its own Internet booking system and call centres.” And on the subscriber side it may not attach conditions “A system vendor shall not attach unfair and/or unjustified conditions to a contract with a subscriber, such as preventing a subscriber from subscribing to or using any other system or systems”. A travel supplier is therefore free to hold more than one GDS contract.

4. Airlines that own a GDS cannot tie commission to it

One more rule protects small travel agencies rather than buyers: a subscriber with fewer than 50 staff and turnover up to £8,700,000 can leave its GDS contract on no more than three months’ notice after the first year (Article 6(2)).

What NDC is, in IATA’s words

IATA describes it as a programme and a standard: “NDC (New Distribution Capability) is a travel industry-supported program (NDC Program) launched by IATA for the development and market adoption of a new, XML-based data transmission standard (NDC Standard).” It is “Available on a voluntary and open basis”, and “The NDC Standard enhances the capability of communications between airlines and travel agents and is open to any third party, intermediary, IT provider or non-IATA member, to implement and use.” The aim IATA gives is to address distribution limitations “by addressing the industry’s current distribution limitations: product differentiation and time-to-market, access to full and rich air content and finally, transparent shopping experience.” The founding document is listed as “Resolution 787 - Oct 2012: a copy of the IATA Resolution, supporting the NDC Program.”

Where NDC and the CRS rules meet

This is our reading of the two texts together, not a statement of settled law. The CRS rules apply to a system holding information “of more than one air carrier”. An NDC connection that carries a single airline’s offers does not obviously fit that definition, and an airline’s own website is expressly outside the display rule:

On the other hand, NDC content delivered through a GDS is content in a CRS, and the display rules apply to how the GDS shows it. So whether a given NDC booking sits inside or outside the code depends on the route it took. For a buyer the practical questions are simple:

• Which airlines’ NDC content can the supplier book, and through which connection?
• Does the booking tool show NDC offers alongside GDS fares on one screen, or separately?
• Do NDC bookings appear in the same reporting, and can they be changed and refunded through the same service desk?
• Are any fees different for NDC bookings?

Those questions belong in a tender. They are in the RFP and ITT template, and the fee side is on what corporate travel management costs.

Why a company buying travel should care

• Content: what a traveller is shown depends on the supplier’s connections, not only on the airline.
• Neutrality: a GDS screen is legally neutral; a direct connection is whatever it is designed to be.
• Data: the law limits how GDS booking data identifies your travel agency.
• Service: changes and refunds can work differently by channel — ask before it matters.

What a travel management company actually supplies is on what a TMC is; the names suppliers give themselves are on what each supplier name means. This page quotes Regulation (EC) No 80/2009 as it stands on legislation.gov.uk and IATA’s description of NDC, read on 2026-09-27; it is not legal advice.

Common questions