Austria and Iron Curtain during Cold War

Question

Winston Churchill's Iron Curtain speech from 1946 contains the following famous passage:

From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent. Behind that line lie all the capitals of the ancient states of Central and Eastern Europe. Warsaw, Berlin, Prague, Vienna, Budapest, Belgrade, Bucharest and Sofia ...

Why did Churchill include Vienna (capital of Austria) in that list? Was it perhaps because the exact fate of Austria (which became fully independent only in 1955) was yet unknown also to him? In 1946 the country was divided into four zones of Allied occupation with the Soviet zone surrounding Vienna but comprising only about a quarter of the city (similar to Berlin). Or was it perhaps because Churchill considered a future neutral state (and that was Austria's designation from 1955) along the Iron Curtain to be de-facto in the Soviet sphere?

I remember from Conrad Black's Franklin Delano Roosevelt: Champion of Freedom that at the Yalta conference in 1945 Churchill had floated the idea of reconstituting the western and southern German-speaking parts of defeated Nazi Germany as a state based on Vienna (both Roosevelt and Stalin disapproved, because of the relation to imperial Hapsburg history), so Churchill certainly was not ignorant about or uninterested in the history or fate of Vienna.

Answer 1

The obvious interpretation is your point that the position of Vienna was similar to that of Berlin: both were in the eastern part of the country, surrounded by the Soviet occupation zone, even if the position within the city itself was different.

So if you drew a line across Europe showing the areas controlled by the Soviet Red Army or by local communists, then both Vienna and Berlin were to the east of that line.