GuiPreissler

While there are no signs of the new SimCity coming to Steam, they do have The Sims 3 plus every single expansion (yes, Seasons and Supernatural included) as well as other Maxis games (Sim City 4 deluxe edition and spore + expansions). So, yes, i'm really hoping they do the same with the new SimCity (I already contacted maxis regarding this but I didn't get any answer yet)

The transports advisor will notify you if it's worth placing an airport. Keep upgrading your commercial zoning (see where is more convinient and stuff like that) and wait until there.