How did american and soviet viewpoints differ over the postwar fate of europe?

The USA and the USSR were at odds over how Europe would be governed after the war.  The USA (and its democratic partners among the Allies) wanted free and open elections in the countries of Eastern Europe coming out from under Nazi domination.  The Soviet Union wanted states allied and aligned with it to prevent any future aggression against the USSR (like how Germany had invaded).  The USSR ended up heavily influencing the Eastern European countries to align with communism, bringing them behind what British prime minister Winston Churchill called "The Iron Curtain."
The situation of Germany itself was also a tension spot.  Germany was divided between the four Allied nations (Britain, France, the USA, and the USSR).  The British, French and American sectors combined their governance of West Germany and West Berlin.  The Americans and their partners sought to preserve democratic freedoms in the area or Germany under their control.  The Soviets blockaded Berlin (located within the Soviet sector of East Germany).  The American side responded with the Berlin Airlift to keep West Berlin free of Soviet control.