Some concepts work well for Simutrans, and others don't.
Let me give you a good example: Taxis. Taxis don't work well with the simulation engine. Sure, they work great in real life, but this is a simulator and game, rolled up into one; and it was created with certain basic decisions already having been made for good reasons. For example, the tile system, and relative size of cities.
If you think about it -- the bus stops we place in game don't really correspond well to coverage over an entire city. There's two graphic scales going on there...
Well, taxis don't fit into that picture.
In the same way, some of these fringe transportation methods don't fit either.
Also, as far as planes landing on roads -- I'm not sure that's a regular occurrence nearly anywhere... Certainly, the vast majority of countries do NOT allow such a thing on a regular, routine basis. Airports exist all around the world.
If you want to land aircraft in a 'remote' part of your map, build a small airport...
Tactical transport is not currently a part of the Simutrans world... OR at least, it happens transparently to the player.
Please remember that the player, in Simutrans, is in charge of a company that tries to make a profit transporting goods that factories in the Simutrans world already contracted with each other for; as well as passengers/mail in/between cities and factories and tourist places...