The end of the second world war resulted in he spiting of Berlin among Russia, the US, France, and Great Britain.
As the Cold War progressed, there was an increase in tension between the western owned part of Berlin and Russia. Stalin seemed outnumbered even though he owned most of the territory than the individual western countries.
In 1948, President Roosevelt, conferred with English, and French leaders to join their occupied zones to creat a New Democratic state of Germany.
Because the Western powers were working with each other, Russia decided to hinder their success in doing so by initiating a blockade around western occupied side of Berlin to stop imports.
And so the airlifts began. The Allies joined resources to send to West Berlin through airplanes.
The airlifts proved to be successful, so Stalin decided to put down the blockade because it was deemed useless.