Probably the largest flight of Arabs occurred in Jaffa in April and May of 1948, and many websites have weepy articles about how the Jews drove the Arabs out of Jaffa, reducing its Arab population from 75,000 to less than 5,000.
What will not be mentioned is the fact that the first refugees from Jaffa were Jews.
In August, 1947, the Arabs started shooting at Jews in Jaffa. Since Jaffa was a predominantly Arab town, the lives of the Jews there were particularly precarious. Arab snipers shot from the minaret of a mosque in the Manshieh Quarter and forced 18 Jewish families to leave the city.
For three months, the families (except for the children) had to sleep outside, until accomodations were found for them in Tel Aviv.
The homes that belonged to the Jews were meanwhile occupied by Arabs.
This time, about 5000 Jews (mostly Yemenites) lost their homes, and the Jewish authorities scrambled to find accommodations for them.
Meanwhile, the Jaffa Arabs who left in November and December of 1947 were hardly "refugees." They were upper-class Arabs who could afford to move to Amman and Damascus and Beirut, in anticipation of a repeat of the 1936-9 riots when they moved as well. Like in 1936, they expected to move back to their houses after things died down. By no stretch of the imagination can these people be regarded as "refugees" even though they are counted as such today.
Their move away from Jaffa affected the rest of the residents, though, as they closed their businesses and unemployment skyrocketed in the coming months. This was one of the major factors behind the mass flight from Jaffa in April and May, 1948.
But the first ones to be forced to leave their homes were not Palestinian Arabs, but Palestinian Jews.