I answered part of this question earlier at http://news.ycombinator.com/item?id=1473748 http://news.ycombinator.com/item?id=1473748 The thing to understand is

I answered part of this question earlier at http://news.ycombinator.com/item?id=1473748 http://news.ycombinator.com/item?id=1473748 The thing to understand is that the airlines publish data that ITA uses. The problem is that it takes an incredible amount of engineering effort and algorithm smarts to go from 'published airline data' to 'this is the cheapest flight from BOS to LAX on 4/20'. ITA does have competitors; historically those competitors offered much lower quality products, although that might have changed. One of the ITA co-founders wrote a presentation on some of these topics at http://www.demarcken.org/carl/papers/ITA-software-travel-complexity/ITA-software-travel-complexity.html http://www.demarcken.org/carl/papers/ITA-software-travel-com...