At the end of the Second World War, in 1945, the victorious allies divided Germany up into four zones of occupation - British, American, French and Soviet Union. The devasted German capital of Berlin was also divided into four separate zones of occupation.
As the Cold War deepened between America and the Soviets, there
was disagreement over the future of Germany.
To force the British, Americans and the French out of West Berlin,
the Soviet leader, Joseph Stalin, began a blockade of the city. Instead
of withdrawing, or using force, to break the blockade, the Western allies decided to airlift supplies into West Berlin via air corridors previously agreed with the Soviets.
The RAF contributed Lancaster, York and Hastings aircrews to
the airlift which lasted from June 1948 to September 1949.
The airlift succeeded in supplying the city through this period.
Despite Soviet harrassment of Allied aircraft, the Soviet leadership could not risk an outright attack in the air without avoiding
full-scale war. The Soviets lifted their blockade in May 1949.