In short
Interline travel is a journey that involves more than one airline under commercial agreements that let the trip be sold, ticketed, and handled as a connected itinerary. It matters because the traveller sees one journey, while the seller and airlines must coordinate rules, responsibility, pricing, and servicing across carriers.
What interline means
An interline trip joins flights from different airlines into one journey. The airlines are not simply appearing beside each other in search results. They have commercial arrangements that allow the journey to be combined and handled in a coordinated way.
For a traveller, the result can look simple: one trip from origin to destination. Behind that simple presentation are rules about whose fare applies, how travel is ticketed, what happens when plans change, and which airline owns which part of the experience.
How it differs from codeshare
Interline and codeshare often appear together, but they are different concepts. Codeshare is about one airline marketing a flight operated by another airline. Interline is about the ability to combine airlines on a journey.
A trip can be interline without being codeshare, and a codeshare flight can sit inside a wider interline journey. The practical question is what the seller is presenting and which rules apply after the booking is made.
The test that matters commercially is whether an extra bought once still holds later in the journey.
| How the journey is put together | What the traveller is actually holding | Whether an extra bought once holds across the journey |
|---|---|---|
| Interline | Connected travel across airlines that have agreed to combine it | Often, though the operating carrier's own rules can still cut in |
| Codeshare | A flight marketed under an airline code that another carrier operates | It depends whose conditions govern the flight actually flown |
| Separate bookings | Unconnected trips that happen to line up in time | No. Each booking is priced, changed and serviced on its own |
Why it matters commercially
Interline creates reach. It lets a seller offer journeys that one airline could not operate alone. It also creates more complexity when paid options, changes, refunds, and disruption handling need to be explained clearly.
Good merchandising keeps the journey context visible, especially when different carriers are responsible for different parts of the trip.
Where ancillary value leaks on an interline itinerary
Interline journeys break the assumption that something bought at the start of a trip travels the whole way. Responsibility is shared across carriers, so an allowance or a service that holds on the early portion may not hold later, and the traveller learns this at a transfer desk rather than at checkout. Your brand sold the trip, so your brand absorbs the reaction.
Commercially that lands on merchandising and on servicing alike. Merchandising has to know which carrier operates which part of the itinerary instead of treating the journey as an undivided block. Servicing has to explain a decision that was never yours to make. Baggage is the usual flashpoint, which is why baggage revenue repays modelling carrier by carrier rather than booking by booking.
Frequently asked questions
What does interline mean?
It means a journey involves more than one airline, with agreements that allow the trip to be sold and handled together.
Is interline the same as codeshare?
No. Interline is about airlines accepting each other's travel on a journey, while codeshare is about marketing a flight under another airline code.
Why does interline matter for sellers?
It affects how the trip is displayed, priced, serviced, and explained when more than one airline is involved.