One of the sources of dispute during negotiations was when the travel restrictions began. At one point the Soviets suggested a start date of March 30, while the Americans held to an earlier date.
The first Soviet travel restrictions went into effect March 31 on rail travel, although some trains got through after that date. The road blockage came later. The road bridge was closed on June 16, although a small ferry on a secondary route was made available, and barge traffic restrictions later still. In any event, all traffic was halted on June 18, not the 24th. The confusion may have come because June 24 was when the airlift started.
The Soviet Union ends its blockade of Berlin on May 12, 1949.
They continued restrictions after that date. (Some of which were simply ignored by the west). Heavy restrictions on road travel only ended in mid - July after the Americans announced that they were planning to send through armed convoys once a week to supply the garrison.
The airlift itself continued through September, going on a 5 day week Aug 12, and finally ending Sept. 31.
Berliners are still free to move around their city,
Not entirely correct. On February 15 the Russians began to block streets between the two sectors (Illing one man who tried to get through) and by the end of April 53 (about half) of the streets crossing the zonal boundry had been blocked.) Passengers on the S-Bahn and U-Bahn were also subject to being stopped and searched and having parcels seized. Workers were allowed to travel to and from jobs, but goods shipments were blocked.
Fianlly, the role of the French must be noted. They favored an early surrender to the Russians in Berlin, but they did contribute by blowing up the Radio Berlin transmission towers.
Primary source: The Berlin Airlift
Ann & John Tusa, Atheneum, 1988.
Thanks for the corrections, and clarifications PAR35.
I'm still trying to figure out why the US and Britain allowed the french to have an occupied sector in Germany. IMHO, they didn't earn the right to one.