I never had trouble with Luke or anyone else being able to step into any old ship and be able to fly it. Consider that we (today) can pretty much drop into any car and drive it, even models we’ve never driven in before. It isn’t a stretch to imagine that in a much more technologically advanced culture, the user interface in flying ships will have been as standardized as is the case for our cars today. You’d learn to fly a ship the way we learn to drive cars. And some people are just better at doing the fancy stuff.