What is Flight API? Use for Travel Itinerary Making Platforms

For any platform selling flights, the API that connects it to airline content is one of the most consequential technical decisions in the build. It determines which airlines you can sell, how fresh your fares are, what margin you keep, and how much engineering effort the integration costs. This guide covers what a flight API does, the types available, the distribution shift you cannot ignore in 2026, and how to choose.

Key takeaways:

• A flight API is the integration layer that lets OTAs, TMCs, and travel platforms access real-time flight data and booking from airlines, GDSs, or aggregators in one connection.
• There are four main types: direct airline APIs, GDS APIs (Amadeus, Sabre, Travelport), third-party aggregators, and meta-search APIs. Each trades coverage, cost, and integration effort differently.
• The biggest shift is GDS to NDC. IATA’s XML-based NDC standard is replacing the 40-year-old EDIFACT protocol, but adoption is gradual: GDS-EDIFACT still accounts for roughly 88% of indirect airline sales (Altexsoft, 2025).
• NDC matters commercially. 87% of travel managers report NDC-enabled connections save money (State of Corporate Travel and Expense, 2025), and ancillary attachment rates reach up to 35% on NDC versus 5% to 8% on EDIFACT (Accelya, 2025).
• Choosing a flight API comes down to content coverage, NDC support, pricing model (per-call versus look-to-book), rate limits, and integration support, not provider brand alone.

I. What Is a Flight API?

A flight API is an interface that lets your platform request and receive flight data from an external source in real time. That data includes schedules, seat availability, fares and fare rules, routing, airport and airline codes, and, for booking-capable APIs, the ability to create and ticket a reservation.

Without an API, a travel platform would have no way to show live flight options. With one, an OTA, travel management company, or booking portal can aggregate content from many airlines through a single integration and let users search, compare, and book. A flight API is a subset of the broader travel API category. For the wider picture across hotels, cars, and activities, see our overview of what a travel API is.

II. The Four Main Types of Flight API

1. Direct airline API

The airline exposes its own inventory directly. This gives you the richest content, the airline’s full ancillary catalogue, and no intermediary markup, but it requires a separate integration per carrier. It suits large OTAs and TMCs with the engineering capacity to manage many connections, and it is the channel where NDC content lives.

2. GDS API

Global Distribution Systems aggregate inventory from most full-service carriers and many low-cost carriers into one feed. The three majors are Amadeus, Sabre, and Travelport (which consolidated the older Galileo, Apollo, and Worldspan systems). One GDS integration gives broad global coverage, which is why GDS remains the backbone of indirect distribution, but it carries GDS fees and historically limited airline merchandising.

3. Third-party aggregator API

Aggregators sit between you and the airlines or GDSs, normalising messy airline implementations into one clean API. They combine GDS, direct NDC, and low-cost carrier content so you integrate once rather than many times. This is usually the most practical option for small and mid-sized OTAs and TMCs that lack the resources to manage direct connections. Examples include Duffel, Travelfusion, Kiwi.com, TBO, and Mystifly.

4. Meta-search API

Meta-search APIs gather and compare fares across multiple OTAs and airlines so users can compare price and options before being redirected to book. Skyscanner is the best-known example. These are oriented to price comparison and lead generation rather than direct ticketing, so they fit platforms whose model is comparison and referral.

III. GDS vs NDC: The Shift Reshaping Flight APIs

If you are choosing a flight API in 2026, the single most important context is the move from GDS-EDIFACT to NDC. Ignoring it means building on a model that is actively being replaced.

NDC (New Distribution Capability) is an IATA standard, launched in 2012, that replaces the 40-year-old EDIFACT protocol with modern XML and API-based communication. EDIFACT could only display limited fare information and could not merchandise most ancillaries. NDC lets airlines distribute rich content, dynamic pricing, and unbundled offers (seats, bags, bundles) directly through APIs, whether direct or via a GDS or aggregator.

The commercial case is real. 87% of travel managers report that NDC-enabled connections save money (State of Corporate Travel and Expense, 2025), partly by avoiding GDS surcharges. Airlines see higher ancillary attachment rates, up to 35% on NDC compared to 5% to 8% on EDIFACT (Accelya, 2025).

But adoption is gradual, and this is the honest part most vendor blogs skip. GDS-EDIFACT still accounts for roughly 88% of indirect airline sales globally (Altexsoft, 2025). According to IATA’s 2025 Annual Review, even leading NDC airlines remain in the setup phase, and many carriers will only begin their full Offer and Order transition in 2028 to 2029. Implementations also vary by airline, so a connection that works with one NDC carrier can fail with another.

The practical takeaway: a flight API chosen today must support both worlds. You need GDS coverage for breadth now and NDC support to capture direct airline content, rich ancillaries, and lower distribution cost as the shift accelerates. This is exactly why aggregators that normalise GDS, NDC, and LCC content into one API have become the default choice for most new platforms.

Because NDC introduces its own message schema, certification tiers, and aggregator landscape that differ from a standard flight API, we cover the implementation specifics separately in our guide to NDC API integration.

IV. Leading Flight API Providers

GDS providers

• Amadeus: The largest GDS, offering both Self-Service APIs for developers and Enterprise APIs for production-scale platforms, with broad global content and NDC support.
• Sabre: Strong in North America, exposed through Sabre Dev Studio, with comprehensive shopping, booking, and ticketing APIs.
• Travelport: Consolidated the Galileo, Apollo, and Worldspan systems, offering aggregated content and NDC connections through a single platform.

NDC and LCC aggregators

• Duffel: A modern, NDC-first aggregator with a clean developer experience, popular with newer OTAs building from scratch.
• Travelfusion: Long-established for low-cost carrier content and NDC connections.
• Kiwi.com: Offers an API with virtual interlining, combining flights from carriers that do not normally connect.
• TBO and Mystifly: Large consolidators with broad global flight inventory, widely used by B2B travel agencies.

Meta-search

• Skyscanner: Partner and affiliate APIs for fare comparison and distribution, used by platforms whose model is comparison and referral rather than direct ticketing.
• Google Flights: A meta-search engine rather than a general booking API. Its data access is restricted to partners, so it is not a drop-in booking integration for most platforms.

Provider capabilities and pricing change frequently, so validate current coverage, NDC support, and commercial terms directly with each provider before committing.

V. How to Choose the Right Flight API

The right choice depends on your platform’s model and scale, not on which provider is best known. Weigh these factors:

• Content coverage: Which airlines, regions, and fare types you need. A regional OTA and a global TMC have very different requirements.
• NDC support: Whether the API exposes NDC content and ancillaries, not just legacy GDS fares. This determines your access to rich content and lower-cost direct airline offers.
• Pricing model: Per-call pricing, subscription, or look-to-book ratio charges. Look-to-book (the ratio of searches to bookings) is the largest ongoing cost in NDC distribution and can quietly dominate your bill if your search volume is high.
• Rate limits and performance: Response time and throughput caps that affect search speed and the user experience at peak load.
• Integration effort and support: Direct airline connections multiply engineering work; aggregators reduce it. Check documentation quality, a test or sandbox environment, and whether the provider offers integration assistance.

VI. How to Integrate a Flight API

Once you have chosen a provider, integration follows a consistent path:

• Define your requirements: Booking versus information-only, target markets, and whether you need ticketing and post-booking servicing (changes, cancellations, refunds).
• Obtain access and read the documentation: Get the API key and study the shopping, booking, and servicing endpoints. Use the sandbox to test before touching production.
• Build the integration layer: Handle authentication, search caching, error handling, and the normalisation of responses into your own data model. This layer is where most of the engineering effort sits.
• Validate responses independently: Confirm fares, availability, and rules against the source before go-live, since airline NDC implementations vary.
• Monitor look-to-book and performance: Track search-to-booking ratios and response times after launch, since these drive both cost and conversion.

For platforms building the full booking experience around this integration, see how a flight API fits into a complete flight booking website, and how the booking flow works end to end in our guide to the flight booking process.

VII. Flight API Cost Considerations

Flight API costs come in two layers: the provider’s API fees and the engineering cost of integration. Provider fees follow per-call, subscription, or look-to-book models, and the look-to-book ratio is the variable that most often surprises teams, since high search volume with low conversion inflates cost. Direct airline integrations carry the highest engineering cost because each carrier is a separate connection; aggregators trade a per-transaction fee for far less build effort. Budget for ongoing maintenance too, since airline NDC implementations change and integrations need upkeep.

Frequently Asked Questions

What is a flight API used for?

It lets a travel platform pull real-time flight schedules, availability, and fares, and, for booking-capable APIs, create and ticket reservations, by connecting to airlines, GDSs, or aggregators through one integration.

What is the difference between a GDS API and an NDC API?

A GDS API delivers aggregated content through legacy EDIFACT-based systems with broad coverage but limited merchandising. An NDC API uses IATA’s modern XML standard to deliver rich content, ancillaries, and dynamic pricing directly from airlines. Most platforms now need both.

Which flight API is best for a small OTA?

A third-party aggregator is usually the most practical choice, because it normalises GDS, NDC, and low-cost carrier content into one integration, avoiding the cost and complexity of many direct airline connections.

Is NDC replacing the GDS?

Not entirely, and not yet. GDSs have built their own NDC connections and remain central to distribution, with EDIFACT still handling roughly 88% of indirect sales. NDC is growing steadily, but full industry transition is expected to continue into the late 2020s.

Conclusion

A flight API is the foundation of any platform that sells flights, and the right one balances content coverage, cost, and integration effort. The defining factor in 2026 is the GDS-to-NDC shift: you need GDS breadth today and NDC support to capture richer, lower-cost airline content as adoption accelerates. For most new platforms, an aggregator that normalises GDS, NDC, and LCC content into one connection is the pragmatic path.

Integrate Flight APIs With Adamo Software

Adamo Software builds custom travel platforms with flight API integration across GDS, NDC, and aggregator sources. Our travel and hospitality team handles the integration layer that determines a platform’s success: real-time search, normalisation across providers, ticketing, and post-booking servicing, with the architecture to manage look-to-book and peak load. Explore our online booking engine development services, part of our wider travel and hospitality software development capability.

Contact us for a free consultation.