There are a bunch. This looks very low-tech, but is completely free and kinda fun for a while: http://www.airline-empires.com/index.php?/page/home.html http:/

There are a bunch. This looks very low-tech, but is completely free and kinda fun for a while: http://www.airline-empires.com/index.php?/page/home.html http://www.airline-empires.com/index.php?/page/home.html This is much more slick: http://www.airlinesim.aero/en http://www.airlinesim.aero/en But none come close to the complexity of the real thing, and the models are unrealistic/can fairly easily be "hacked" (print money by giving away flights but charging $1000 for meals, etc).