I doubt if users would have paid much for this kind of App. As its use-case seems to me, a cousin of lot of other free apps like maps (directions), which are done by giants. So basically its something which people need, but have mental categorization of it as a near-free thing.<p>For roughly the same amount of effort, that you put in this app, you could have a flight search engine. Where you will get something per transaction.<p>Not taking away from the app. From what I read here, it seems it was nicely done, and must have been quite useful. But its about how much people can pay per transaction (if I can call it that.). Freemium ad based model, has been the dominant Internet culture so far, for information from the web. That is a big barrier, in my experience for these kinds of apps to do well.