We have long had an XML API for everyone to search for tickets on their website.
I will quote a corporate blog:
Hi, Habrahabr!
We are one of the most modern (and cheap) air ticket services.
Eviterra.com has not written anything here for a long time, because we are preparing some very interesting news: for example, we will soon have a very significant interface update (this, by the way, no one has ever done before), bonus programs and much better.
')
Well, in the meantime, there is great news for all geeks, web developers, marketers, startups, hipsters, aviators and more. If you have a website where you want to search for flights, then you can do it with us right now.

We have an excellent XML API for everyone. With it, you can do a search for air tickets and display the results completely in your design. To purchase, the user is redirected to us, and you get half the income from the ticket sold through you. All statistics, of course, available in real time.
Interesting? Send us a small description of your project (or future project) at
support@eviterra.com and we will tell you what to do next.