How did hitler manipulate the term aryan for nazi purposes?

The term aryan is a term used to describe a race or a population as noble and better than other races. He used it because of the indo-aryan migration theory which states that people settled Europe from the hindu parts of the world meaning that one could say that people who descend from the Indo-European languages are aryan. He used this to explain that white people from Europe are Aryans and that they are better than other races.