Bus drivers only take a few weeks because they have prior driving licence experience on the road, typically for some years; it is just a new vehicle under much the same regulations and environment. Back in the 1930s-50s the typical bus driver had no prior experience with a car, and it took much longer.
Having handled all of a car, bus, train, boat and aircraft, I can tell you that the aircraft needs far and away the most skill, and the boat comes second. The train is pretty straightforward in comparison nowadays, though I suspect a steam locomotive was up at aircraft levels.
Having handled all of a car, bus, train, boat and aircraft, I can tell you that the aircraft needs far and away the most skill, and the boat comes second. The train is pretty straightforward in comparison nowadays, though I suspect a steam locomotive was up at aircraft levels.