The Berlin airlift was a time of blockade of the land (road and rail) connection of West Berlin and West Germany - it was an attempt of the Soviet Union to exercise pressure on the West and to release control of West Berlin.
It's lasting effects were that it showed to both the Soviets and the Western Bloc that the West is capable of sustaining West Berlin, which had in influence on the power play between the two and it strengthened the position of the Western Powers in West Berllin.