[perfect-blue]

I have really enjoyed AirportCEO on steam. I would check it out, might be exactly what you’re looking for. Another option would be to get the mods for MS Flight Simulator that allow you to create an airline and make money and grow your business, etc.

[ThunderSizzle]

Airport CEO is good because there's nothing better in the space.

I do feel the space is wide open in transit based games. Transport Fever, for example, leaves a lot to be desired while still being awesome too.

[ryandrake]

I tried Airport CEO but never really got into it. Too much focus on running the business and designing the interior of the terminal building, and not enough detail/control on designing runways, taxiways, hangars, lighting, and performing various airport ops. It's pretty nice if you're interested in a business sim though.