Flight API vs GDS vs NDC Aggregator vs Consolidator

GDS, NDC, consolidator and flight API are often discussed as if they are interchangeable.

They are not. GDS, NDC aggregator and consolidator are content sources, each with its own contract, settlement path and servicing rules. A flight API is the technical interface your booking engine calls. A GDS, an NDC aggregator, a consolidator, a direct airline connection or a blend of all of them can sit behind it. Before you compare providers, find out which sources sit behind the API you are buying. That answer decides what you can sell, at what margin, and who fixes the booking when it changes.

Definitions.

• GDS (global distribution system): a shared network that stores airline schedules, fares and seat availability and lets subscribed agencies search, book and ticket them. Amadeus, Sabre and Travelport are the three main global GDSs. See the GDS glossary entry.
• NDC aggregator: a technology provider that connects to many airlines' NDC APIs and gives you one normalised integration in place of one build per airline. NDC (New Distribution Capability) is IATA's standard for airline offers and orders.
• Consolidator: an accredited wholesale agency that sells airline tickets to other agencies, often at negotiated net fares, and issues and settles those tickets under its own accreditation.
• Flight API: the programmatic interface your booking engine calls to search, price, book and service flights. Its content depends entirely on the sources behind it.

TL;DR

• GDS: broad full-service airline content, mature servicing tools, one subscriber agreement. Some richer airline offers now sit outside classic GDS content.
• NDC aggregator: one integration to many airlines' NDC offers, with bundles and ancillaries. Coverage and servicing depth vary by airline.
• Consolidator: net fares and ticketing under the consolidator's own accreditation and settlement (IATA and BSP, or ARC in the United States). You work inside its contracts and its service desk.
• Flight API: the interface only. Ask which sources sit behind it and how they are compared.
• Growing sellers usually combine sources. The hard part is comparing them on one itinerary and servicing every booking the same way.

What is a GDS and how does it source flight content?

A GDS (global distribution system) is a shared booking network that airlines use to distribute schedules, fares and seat availability to subscribed travel agencies. The GDS prices itineraries against the airlines' fare rules and returns bookable options to those agencies. One subscriber agreement gives an agency access to hundreds of carriers. That breadth is why the GDS became the default source of full-service airline content.

The commercial relationship runs in two directions. Airlines pay the GDS a fee for bookings made through it. Agencies sign a subscriber agreement, and many receive incentives tied to the volume they book. To issue tickets, an agency needs its own accreditation (IATA in most markets, ARC in the United States) or a ticketing partner such as a consolidator.

The strengths are breadth, standard formats and mature servicing. Exchanges, refunds, voids and schedule changes follow established workflows that most agents already know. The limitation is richness. Classic GDS content was built around filed fares and seat availability rather than dynamic bundles, although GDSs now carry branded fares and some ancillaries too. Some airlines now keep certain fares, bundles or ancillaries for NDC and direct channels, and many low-cost carriers are not fully present in it. Our comparison of NDC vs GDS covers that shift in more depth.

What is an NDC aggregator?

An NDC aggregator is a technology provider that connects to many airlines' NDC APIs and gives travel sellers one normalised integration in place of one build per airline. NDC lets each airline build its own offer (the fare plus seats, bags and other extras) and send it through a modern API. The catch is that every airline implements the standard its own way. Versions differ. Supported messages differ. Servicing functions such as exchanges and refunds arrive airline by airline.

The aggregator absorbs that variation. You integrate once, and the aggregator maintains the connections to each airline's NDC API. Commercially, you sign with the aggregator. Depending on the airline, you may also need your own agreement with the carrier or your own IATA number for ticketing and settlement.

The strength is access to richer offers: branded fares, bundles, ancillaries and some fares that appear only in NDC. The limitation is coverage. You reach only the airlines the aggregator has built, and servicing depth can differ from one airline to the next. Some changes may still need manual handling or a call to the airline.

What does a flight consolidator do?

A consolidator is a wholesale agency with its own accreditation, usually IATA with settlement through BSP (Billing and Settlement Plan), or ARC in the United States. It negotiates net fares with airlines on routes where it has volume. It then sells those fares, and often published fares too, to other agencies. You add your markup and sell. The consolidator issues the ticket and settles with the airline. You pay the consolidator, usually in advance or on agreed credit terms.

The strengths are access and speed. You can sell and ticket flights without your own accreditation, and net fares can beat published fares on the consolidator's strong routes. Many consolidators also run a ticketing desk that handles tricky reissues for you.

The limitations follow from the same structure. You can sell only what the consolidator has contracted. Part of the margin stays with the consolidator. Changes, refunds and schedule disruptions usually go through its desk and its hours, unless it offers self-service tools. Your cash flow also depends on its credit terms. Agency debit memos (ADMs), which airlines raise for fare or booking rule breaches, go to the ticketing agency, so with a consolidator they usually reach you through its desk.

What is a flight API, and what sits behind it?

A flight API is a delivery mechanism, not a content source. GDSs, NDC aggregators, consolidators, airlines and travel platforms all offer flight APIs. Behind any one of them you might find:

• a single GDS, wrapped in a simpler interface;
• an NDC aggregator's set of airline connections;
• a consolidator's net fares and ticketing;
• a direct connection to one airline;
• a platform that combines several of the above into one search.

When a provider says "we have a flight API", that sentence tells you nothing about breadth, fares or servicing. Ask which sources are live today, how the same itinerary is compared across them, and which servicing functions the API exposes. Exchanges, refunds, voids, seat maps and post-booking ancillaries matter as much as search and book.

How do GDS, NDC aggregator, consolidator and flight API compare?

Who handles servicing after the booking?

Who services a booking depends on the source it came from: your own team for GDS bookings, each airline's NDC setup for NDC bookings, the consolidator's desk for consolidator tickets, and the airline's own API for direct bookings.

• GDS bookings: your agents or your platform handle exchanges, refunds, voids and schedule changes through standard GDS workflows.
• NDC bookings: servicing runs through each airline's NDC implementation. Some airlines support full self-service changes through the API; others still need offline handling.
• Consolidator bookings: the consolidator owns the ticket, so changes and refunds go through its desk, on its timelines and under its fees.
• Direct airline bookings: servicing follows that airline's own API and policies.

An agency that sells from four sources therefore runs four servicing processes. Before you add a source, ask how a schedule change on one of its tickets reaches your team, and who fixes it. For how airline distribution fits together end to end, see how airline B2B distribution works.

How hard is it to implement a GDS, NDC aggregator, consolidator or flight API?

Implementation effort grows with every connection you own yourself.

• GDS: a subscriber agreement, the GDS's own API or terminal, and certification before go-live. Each additional GDS repeats much of the work.
• NDC aggregator: one technical integration. Each airline may still need onboarding, testing and sometimes its own agreement.
• Consolidator: web portal access is usually quick to set up. An API connection takes longer, and every consolidator's API is different.
• Direct airline API: one build per airline, maintained for as long as you sell that airline.
• Flight API from a travel platform: one integration, with the platform maintaining the sources behind it.

The build is only the first cost. Airlines change versions, fare rules and servicing messages on their own schedules, and every source you own directly adds to that maintenance. Our guide to white label vs travel API vs custom development covers who carries that work under each technology model.

Why do agencies and OTAs combine several flight sources?

No single source covers everything a growing seller needs. The GDS gives breadth across full-service carriers. NDC gives richer offers on the airlines that have built them. Many low-cost carriers are easiest to reach through their own direct connections. A consolidator can beat published fares on specific routes and issue tickets for you.

Combining sources is therefore common, especially among agencies and OTAs past their first stage of growth. The question is how many connections your own team has to build and maintain, and whether every source returns into one search with one servicing process. If you are reviewing your current setup, our guide to GDS alternatives for travel agencies covers the main options.

What does a combined setup look like in practice?

An illustrative scenario, not a customer story. A mid-size agency sells leisure and small-business travel from one GDS. Its agents see two problems. Several airlines now sell their best bundles through NDC, and its long-haul fares on its busiest routes are not competitive. The agency adds an NDC aggregator for the bundles and a consolidator for net fares on its busiest long-haul routes.

Content improves. The workload also grows. Agents now search three screens and compare prices by hand. Each source has its own servicing route. Finance reconciles three supplier statements. One fix is to bring as many of those sources as possible into one platform, with one search, one booking flow and one back office.

How should you choose your flight content mix?

Start from what you need to sell, then pick the fewest connections that cover it.

• Choose a GDS if breadth across full-service carriers matters most and your agents rely on standard servicing workflows.
• Add an NDC aggregator if the airlines you sell most now keep bundles, ancillaries or fares in NDC.
• Use a consolidator if you sell flights without your own accreditation, or need net fares on specific routes.
• Buy a flight API from a platform if you want several sources through one integration, without owning every connection yourself.

Many sellers end up with a combination. The technology decision that matters is whether your platform carries that combination through one search and one servicing process.

What should you ask a flight content provider before you sign?

• Which sources sit behind your API today: GDS, NDC, consolidator, low-cost or direct airline connections?
• Which airlines are live on each source today, and which are on a roadmap?
• How do you compare and de-duplicate the same itinerary when it comes from two sources?
• Which servicing functions work through the API: exchanges, refunds, voids, schedule changes?
• Who issues and settles the ticket for each source, and which accreditation does that need from us?
• Can we keep our own GDS contract and our own negotiated fares?
• What happens to our bookings and data if we leave?

How does altovo bring flight sources together?

altovo (formerly easyGDS) is a travel commerce platform that puts GDS, NDC and low-cost content behind one search. As of October 2026, 650+ airlines are bookable on the platform, including NDC. Agencies can connect their own GDS and keep it: the platform sits alongside existing GDS contracts. Negotiated rates you already hold can be mixed with the altovo network, and results come back as one set rather than a screen per supplier.

Travel agencies sell through a white-label B2C storefront, a B2B agent portal for teams and sub-agents, or REST and GraphQL APIs for their own front end. Self-serve travel agent accounts can be live in under 10 days, from sign-up to live bookings. See altovo for travel agents and the connectivity layer behind it.

Talk to altovo

Frequently asked questions