“We say at every opportunity we have that Syria, Iraq and other places in the geography [map] in our hearts are no different from our own homeland. We are struggling so that a foreign flag will not be waved anywhere where adhan [Islamic call to prayer in mosques] is recited.”
Apparently Erdogan means at the very least the recapture of all the lands once held by the Ottoman Empire. That’s not just Greece, as in the article title below. That’s also Bulgaria, Romania, Yugoslavia, Algeria, Syria, Iraq, Israel, Egypt, Algeria, Tunisia, Morocco, and more. How seriously this can be taken is anybody’s guess, but it shouldn’t be dismissed out of hand. Erdogan is already moving against the Kurds in Syria, explicitly calling the action a “jihad” and invoking the Ottoman era repeatedly.
And “We are struggling so that a foreign flag will not be waved anywhere where adhan [Islamic call to prayer in mosques] is recited” refers to far more than just the old Ottoman domains. That means everywhere there are Muslims in Europe and everywhere else. The caliphate is, in Sunni Islamic theology, the sole legitimate government for Muslims on earth, to which all Muslims owe allegiance. Erdogan is saying more clearly than he ever has before, as far as I know, that he is going to restore the caliphate. And he is virtually promising war with the non-Muslim (at least for now) states of Europe.