Used fly.com to book a roundtrip ticket and found when I needed to change my itinerary by 1 day, same flight, I could only change through the justfly.com agency. I called directly to American Airlines and they gave me the cost to change the flight with them - $150 bus said they couldn't make any changes only Justfly.com could change. When I called them the change fee was $275 with their feeds tacked on top of the airfare. Buyer beware. They are not there to help you with your air travel, - not flexible, not helpful, just making money off people who stumble on their site. Please avoid and save yourself $$$ on the back end of your airfare purchase.