What is an interline ticket? Why it’s important

Amin Benzaza

Hong Kong International Airport Terminal

You may have booked an interline ticket in the past without even knowing it. One of the great things about flying is that airlines work together even though they compete against each other.

I wanted to fly from Montreal to Doha. I could not book Qatar Airways since they only fly 3 times a week. That frequency did not fit my schedule. However, while I was browsing on Expedia.ca, an interesting itinerary popped-up in my search results.

Definition of an interline ticket

An interline ticket or ticketing (interlining) is an agreement between two airlines to transport passengers on itineraries that require multiples flights. This kind of agreement allows passengers to fly without having to worry about luggage transfers, transit or in some cases check-in multiple times. 

This benefits passengers and airlines: more shared revenues for the airlines and a smooth travel experience for passengers.

Interline agreements can occur between competing airlines and outside of alliances as well. Airlines will showcase a list of its interline partners on their site. As you can see below, Swiss International Airlines has a lot of interline partner airlines and many of them are outside the Star Alliance.

Swiss International Airlines interline partners list
Swiss International Airlines interline partners list

How can I purchase an interline ticket?

There are two ways to purchase an interline ticket. You can either call a travel agents or book it yourself with an OTA.

Travel Agent

Travel agents can come handy. They have access to the reservation systems, build your itinerary and offer you the best option at the best price. Take a chance, contact a travel agent and see how he or she can help you.

OTA (Online Travel Agency)

An OTA is a travel website which sells travel products such as flights, hotels, car rentals and cruises. Expedia.ca, Booking.com, Hotels.com are just a few that you may already know. Let’s use my itinerary search as an example.

I want to fly Montreal to Doha. However, I want to get to Doha at the earliest time. Also my return leg will be from Zurich to Montreal. I chose Expedia.ca for the example:

Interline booking example on Expedia.ca
Interline booking example on Expedia.ca

I checked the multi-city booking option under the flights tab.
The results are showcased by either price, duration (shortest or longest), number of stops and so on.

Expedia.ca interline multi-city results
Expedia.ca interline multi-city results
Expedia.ca interline multi-city results filtered by shortest duration
Expedia.ca interline multi-city results filtered by shortest duration

As you can see there are many airline combinations. As a traveller, you can choose the most convenient route for your needs. Also, an interline airfare behaves like any other airfare: you get to earn miles.

Make sure you provide your frequent flyer program numbers. In this case, I will add my Aeroplan number for the Swiss International Airlines portion and British Airways Executive Club number for the Qatar Airways portion.

Avios & Tier points earned on Zurich to Doha Qatar Airways flight -  O fare
Avios & Tier points earned on Zurich to Doha flight

What is a codeshare agreement?

Not to be confused with interline, a codeshare agreement is a flight that is marketed by two or more airlines. Each airline will use its own designators: airline code and flight number.

For example, American Airlines operates flight AA106 linking JFK to London Heathrow. This flights is also marketed and sold by AA’s partners:

British Airways: BA1517
Iberia: IB4222
Finnair: AY4018

I wrote a detailed post about codeshare and its benefits for travelers and carriers.


I have booked my interline multi-city airfare. I was able to build my own route with schedule preferences. Have you ever booked an interline ticket in te past? What was your experience like?

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