The airline you book with is not always the airline you fly with.

This is a common scenario with travelers who unknowingly booked a codeshare flight.

Airlines that are not members of the same alliance can enter into a codesharing partnership.

Planes at San Francisco Airport

Credit: Justin Sullivan/Getty Images

Read on to find out more about codesharing and how it could affect your next flight.

What are the benefits?

While it may seem counterintuitive, codesharing can be beneficial for both airlines and passengers.

It allows airlines to sell tickets for routes they don’t actually fly.

It also helps with customer loyalty.

How can you tell if you’re on a codeshare flight?

The DOT requires airlines to clearly disclose when a flight is operating as a codeshare.

When this happens, the words operated by and the other airlines name will appear on all ticket information.

How do fare classes work on codeshare flights?

Every airline has its own policy, and the standard for fare classes might vary by partnership.

Which airline should you check in with at the airport?

However beneficial, codeshare flights can also be deeply confusing and problematic at times.

Issues could arise when you go to check a bag or look for support at the airport.