The title itself, "A Conneticut Yankee in King Arthur's Court," suggests the incongruity of such a man as Hank Morgan living in "Merry ol' England."
Unlike the nobles who themselves are part of the Middle Ages, Hank Morgan is an anachronism who lacks understanding of the supersitious and naive peasants. Morgan assumes that his reforms will benefit the people without considering problems that he might create through his reforms. For instance, he creates factories without considering how such factory work will affect the peasants.
Hank Morgan is like the nobles in that he profits from the work of the peasants. For example, he profits from the miller-gun for dispensing currency since he himself is a gunsmith. Arrogant, Morgan is like the nobles in his false pride. He foolishly seeks to foil Merlin by outdoing the magician's tricks; he gets the king to travel incognito and thereby makes it easier for the king to be captured. And, like King Arthur, Hank Morgan has the tragic flaw of self-deception. While Arthur fails to perceive the love triangle in which he is involved, Morgan flatters himself into believing that his modern ways are superior to those of the Middle Ages.
The most salient difference between Hank and the nobles is that Hank is from a more advanced society and has a knowledge of technology that is unknown to anyone else. Ironically, his knowledge of the modern equipment gives Hank the same attitude of superiority that the nobles share. Thus, his one difference is also his similarity to the nobles.
Hank, like the nobles, is very confident and sure of himself. He exudes an air of power and has quite the ego. The nobles in the story, such as King Arthur, also share these qualities of confidence and self-assurance. However, Hank is different in that, for one, he has time traveled to King Arthur's court, and therefore he has knowledge of advanced technology and updated ways of conducting politics and government.
Refer to: http://www.enotes.com/connecticut-yankee/characters