Aristotle and Plato hold different models of what they consider ethical and moral grounds. And both set out to find the ideal society which would enable us to attain the best human life possible.
First, we must understand what happiness means to these philosophers. Eudaimonia, (Aristotle’s term for the highest good, personal happiness to the Greeks, the state of happiness as an action, something in motion – to flourish) has the connotation of blessedness and not cheerfulness, in the sense that it holds a divine element. for Aristotle happiness means living a life that right-minded people would admire and wish to lead themselves. Happiness is not the means to anything. Happiness is the most final end, since there is no further purpose for which we wish to be happy. As an example, Aristotle believes that there are good reasons to dismiss certain lifestyles as fulfilling happiness. For example: wealth is not happiness although many would disagree. Money will not make you happy all by itself since, since it is not wealth in itself which makes you happy but rather what the wealth may buy you. Aristotle explains that often wealth and honor is a misguided goal in the pursuit for happiness. If I am seeking to be honored this makes honor secondary in the pursuit of happiness since what we are really after is the good and best life which allows us to be honored by others. And thus, we must care for what is exactly we are being honored for and they must be for the right and ethical reasons. Since it is a life that is worth honoring which would then lead me to earn, in the most moral of ways, the admiration of others.
Aristotle suggests that we can discover the answer to true happiness if we answer the question of what our purpose is in the world as human beings. That being a good human must include primarily of doing whatever it is that humans do. In a sense, we must find our true function and then exercise this function to the best of our ability. Making the good life a life where we use our abilities to their maximum capacities, and in the right way. As to fulfill our purpose as good beings in the fabric of human life. A way to think of this would be the example given of a car and its parts. Our body has limbs which all serve certain functions, just as a car parts would do the same. So, we then must as a whole have a function to pursue, just as a cars whole function is to take you from point A to Point B. All the elements surrounding us have functions and so it would be odd to think that we would not. Our purpose then must be unique to our being as humans, which cannot be shared with other entities around us. And it is the use of reason which is then what distinguishes our being from others. In this sense Aristotle is explaining that to live our happiest life we must have an excellent use of reason and be able to use our rationality to best of its ability.
Virtue uses reason to perform the right actions and do the right things which are needed of us. It is reason which allows us to confront each new situation as it arrives and pursue the correct and right course of action in each given case. It is to be thought of a sort of balance of two extremes, that virtuous action is the harmony between an excessive tendency and tendency towards deficiency. In short, it can be thought of as a sort of ethical or moral recipe where you chose to do what is just right, for just the right reasons and enjoy doing so. Virtue is a mean for attaining our eudaimonia. And virtuous actions are in fact pleasant in themselves.
It is important to note that Aristotle believes that we must grow up in a healthy society in order to be virtuous since Aristotle believes that virtue is achieved through habituation. Doing something over and over again until it may become natural to us and doing those things in the right manner, to just the right extent. So we thus develop our virtues as we are children and they grow as we get older and are able to apply them to the world.
‘’Human good turns out to be activity of the soul in accordance with virtue’’  In this respect both Plato and Aristotle’s view of what is good can be seen as the same. Since Aristotle refers to virtue as being the potential excellence that a human could have, and in this sense, it seems this is what Plato was referring to in that it is this ‘’excellence’’ in which Platos individual in society is striving after in the pursuit of happiness. And in both cases the good stems from the soul. Both philosophers believe that happiness is in coordination with the exercise of the soul and the ongoing actions one does in order to pursue this integral self fulfillment. 
In The Republic we see for Plato that it is necessary for not only for ones self to contain and exercise virtues but the state as well. More specifically virtues of temperance, wisdom, justice and courage. In book IV of the republic, Plato speaks on three virtues which hold the state and individual together: wisdom which is active in the state and reason in the soul, courage which is active in the state and will in the soul and finally temperance which is active in the workers of the state and the appetite. (soul) What keeps these three different sets of virtues in alignment is justice. Where the state is the actualization and real-life representation of which justice is the idea, being that justice is an irreplaceable quality of moral life. The state is just when all the individuals are fulfilling their purpose in nature. And it must be several parts of one soul that fulfill their proper function. Although justice is the one holding all these virtues together it is the virtue of wisdom which is in control. Aristotle also suggests that justice is of importance when he mentions that it is not only the state which must be in line with the right and good rule but one that crucially implies it, which is virtue. 
Another difference between the two philosophers is when they speak in terms of virtues as an entirety. Aristotle is concentrating much more of his work on virtues then Plato does and gives us a more intellectual definition. Although both agree on wisdom as the primary virtue. Since it is wisdom which allows us to have self-knowledge and in doing so we can realize our innate and unique talents/daimon which make us who we are and fulfill our functions as beings in the world. The active use of reason is how we acquire knowledge and thus is the highest of the virtues for our being. And this is also clear for Plato in book IV of the republic that we must have knowledge in order to know our daimon. Which will then lead us to integrity, which then leads us to continuously follow our daimon and our true paths in life as human beings. 
In conclusion, both Plato and Aristotle make it clear that we as individuals must develop our moral characters and act ethically in our being to attain the highest good in life and in state. To be just and use our reason in the working of virtues, as well as, ethics and politics and to continuously keep these active as to serve our purpose in the fabric of human life. In my opinion although both philosophers bring up substantial points in attaining a good and ethical life they both seem to lack something when it comes to the virtue of humility. Philosophers are held to the highest’s standard in those who would fit best to rule the state since they would be best suited to be active in the virtues stated throughout this post. Being that it is the philosophers who are closest to the G-ds and have attained happiness through the exercise of virtues. On the other hand In terms of living the best life we must also ask ourselves: are we doing these actions solely as tools for our own enjoyment instead of being completely selfless? What about treating others well for their sake? Although I agree heavily with much of both Aristotle and Plato’s ethics, this a point which I think has not been raised and is somewhat the catch 22 of the idea of Eudaimonia and the active use of our virtues as a whole.
 Aristotle, Nicomachean Ethics, p.877 1098a
 Aristotle, Nicomachean Ethics, p.880 – 1102b
 Aristotle, Nicomachean Ethics, p.880 – 1099b
 Aristotle, Nicomachean Ethics,
 Aristotle, Nicomachean Ethics, p.879 -1099a
Aristotle, Nicomachean Ethics, p.880 1099b
 Plato, Book IV, The Republic
 Plato, Book V, The Republic