The whole "Aryan race" ideology was based on a number of dubious scientific and historical "proofs" that the Aryan race were superior to all other races...well, somebody else who knows more about the ideology of Nazism can elaborate further for you. Of course Hitler regarded himself as a member of this "race", where his conception of the Aryan race extended to all Germanic and Nordic peoples. So as an Austrian he obviously regarded himself as belonging to that group.