In Mein Kampf declared his family to be "Bavarian by blood".
On 22 February 1933 Hitler gave a public speech and said:
Und Sie mögen eines zur Kenntnis nehmen: Ich selbst bin meinem Herkommen nach, meiner Geburt und meiner Abstammung nach ein Bajuware. Zum erstenmal seit der Gründung des Reiches ist die Würde Bismarcks in die Hände eines Bayern gelegt worden.
Was it his way of thinking that Austrians are Bavarians (Germans) due to the history of Austria since Austria was created as a borderland (Margraviate of Austria) of Bavaria in 976?And you may take note of one thing: I myself am a Bavarian according to my origins, my birth and my descent. For the first time since the founding of the empire, Bismarck's dignity has been placed in the hands of a Bavarian.
It's also worth noting that Hitler's birthplace, Braunau am Inn, has swapped between Austrian rule and Bavarian rule quite a few times in history, but since 1816 it has been under Austrian rule.