|Image via CrunchBase|
I have used expedia and cheapoair to get a quotes for airline tickets but found it does not give me a good price when there is more than one transit. I recently found Momondo is a good site when you have multiple transits. I was able to print the quote and took it to my travel agent to get it matched. Next time, I am actually going to book the tickets via the site.
It is a Danish company and they are in the business since 2006.
Here is more info about the company and some reviews about the company.