FSX/P3D. Seasons, Roads, Bridges, vegetation, night lighting... oh yeah, and of course the airport. PacSim is showing the surroundings of this project that is far more than just an airport scenery, it's an entire city! Many more screenshots are now available via PacSim's Facebook page. Sorry no source link as that's hard to do from my phone which I am using for this post. I'll update that later. Thanks to several readers for the tipoff!
Updated with source link.