Seventy-seven years ago today, on April 24, 1948 (March 16, 1948 lunar calendar), Soviet fighter jets collided with British cargo planes. On April 24, 1948, the United States and Britain had opened an air supply line to deliver food and supplies to Berlin in order to thwart the Soviet blockade aimed at driving the Allies out of the former German capital. The air route was opened after the Soviet Union imposed restrictions on trains and transportation across the Allied front to Berlin. Earlier this month, the Soviet Union refused to allow American and British military trains to travel through Soviet territory to Berlin unless they were inspected by Soviet government departments. The United States and Britain refused the Soviet request for inspection. The Soviet Union imposed the same restrictions on ships and forced the inspection of all vehicles on the only highway connecting Germany with the West. In an increasingly cold war atmosphere, the Soviets tried to squeeze the Allies out of Berlin, which was already under the control of the Big Four, by cutting off their supplies. But the Soviets did not block airlifts to Germany, unless the Soviets wanted to provoke a major crisis by destroying Allied aircraft. Soviet fighter jets buzzed above American transport planes, but did not bother them. The Soviets apologized after a Soviet fighter jet crashed into a British airliner.