I found this game a long time ago, so I'm not sure why I chose this one over others.  However, I really like the open worlds because I like being able to open flights anywhere in the world.  I don't really play in the other worlds and I don't think I would play very often if the open worlds were not available.

Although I find this game a lot of fun, one minor detraction is spam airlines that schedule an unrealistic number of seats on a route.   I'm currently playing in one of the open worlds, and, to take just one example, the top-ranked airline has scheduled over 50,000 daily seats on the route between Galesburg and Dubuque.  I'm guessing there must be some bug in the game that allows them to reap unlimited profits by doing so.  This problem could be solved if every airline was limited to scheduling no more than 2x or 3x the number seats than the daily demand on any route.  For example, if the route A-B had a daily demand of 100 seats, then no airline could schedule more than 200 or 300 daily seats on the route.  This would allow all airlines to compete fairly.