Nuvei offers solutions for processing airline ticket payments:

Airline Addendum

The Airline Addendum specifies passenger details as well as the details of the airline ticket, flights and flight legs.
Simply include an Airline Addendum in your /payment request (createPayment() for Web SDK).

External Authorization Addendum

The Airline External Authorization Addendum is an advanced solution which allows you to send airline ticket authorization requests directly to card schemes, using a GDS system (Global Distribution System).
After some transformations, you complete the payment process by sending the “validated” responses in /settleTransaction requests, which Nuvei uses to transfer the funds to the relevant airlines.