In some ways an expert would be someone that knows what he does not know, one can be and "expert" at training students but not the best flyer at the field, the best flyer may get a student in the air but not teach him much. That is just one example. In all I feel an expert can do just about fly anything and bring just about any plane down in one piece.
But I don't know, I am about as far away from an expert as one can be
Jon