In the PluginsExtra pack there are a host of very nice sprites for automobiles, ferries, large freighters, airplanes, etc. Unfortunately, they are all immobile dummies.

It would be nice if we could make them move, and even nicer if they could carry passengers and cargo just like trains. Maybe we could reuse current code and introduce variants of tracks that are abstracted routes for other kinds of vehicles. A shipping route, for example, could appear as a darker blue line on water.

I remember in ATrain-4, there's an option to build some city-wide project, such as the Shinkansen, Airport (though you will not operate it, just donate the cost, afterall, it's good to the city and your company).

We might consider to add this kind of "project" type vehicle as well.