Hummmm ...., I can tell you that going direct to an agency or calling them you will you see the best prices and options for tickets. They have screens that the general public can't see. Also, sometimes cheapest isn't always Better... Consider the route you need to take, how many stops the traveler has to make, how many delays the weather can play into it. Just ask for best routes, for the best price to get to your destination with the least amount of stress and delays on the traveler.

From Doha to USA with routine delays to change plans you are looking at atleast 21hours total trip time. Not to mention being at Doha airport atleast 2 hrs in advance. :s
There are travel agent ticket consolidators that work with specific airlines on line. Goggle that for options as well.
Salam