Answer:
The US and Britain would have maintained the airlift for longer because it was in their interests to prop up West Berlin.
Explanation:
After the end of the Second World War and the destruction of the Nazi regime, Germany was split into four occupation zones among the victorious Allied powers: The Soviet Union, the United States, Great Britain, and France. The German capital, Berlin, was split in four as well. However, Berlin was located deep into the Soviet zone, which led to a series of disagreements and problems as the Cold War drew the former allies apart.
A currency reform in the Western occupation zones threatened the economy of the Soviet zone. The Soviets opposed the reform, and when the Western powers refused to back down, they closed all land links between West Germany and West Berlin on 24 June, 1948. The US and the UK responded by initiating the Berlin Airlift (26 June 1948 - 12 May 1949), a massive aerial operation that ferried fuel, food and other supplies to Berlin for nearly a year.
By the spring of 1949, the Soviets appeared convinced that the Western powers would keep the operation going indefinitely. At the same time, the economic blockade imposed on East Germany in retaliation was choking its economy. The Soviets finally lifted the blockade on 12 May 1949. In the midst of the early stages of the Cold War, the US and Britain would have maintained the airlift for longer because it was in their interests to prop up West Berlin. The capitalist powers felt that communism was a major threat, as the communists were immensely popular in Europe after their major role in the defeat of Nazi Germany. In order to counter this, the US invested massively on the ailing European economies through the Marshall Plan. The economic aid provided by the US helped rebuild the European economies and made socialism a less attractive choice for them.
