I'm going to avoid the political aspects of what constitutes with or against Israelis or Palestinians, and instead will focus on pre-WWII history.

Relations between Israelis and Arabs were generally not peaceful throughout the period leading up to WWII. There were tensions, which grew quite a bit, and there was also quite a bit of conflict. There are the commonly understood historical events that one can point to, like Arab riots in 1920, 1921, and 1929. There are the conflicts that resulted from the Arab Revolt of 1936, which lasted through 1939, and which was principally against the British but also included many attacks (and counterattacks) on Jewish neighborhoods and Arab neighborhoods.

This isn't to say that there weren't also times of calm, or that the entire area was a roiling mess. There were conflicts, true, but there were also moments of coexistence. Arabs were still, in some cases, employed as laborers on Jewish-owned properties, even though there were disputes over this. Arabs viewed Jewish-owned properties as displacing Arab peasants and furthering Zionism at the expense of a fully Arab Palestinian state, which Arabs wanted, while Jews wanted to have Jewish-only labor so they could establish an independent economy to justify their desire for a separate state. There were also moments of coexistence among the moments of conflict. During the Hebron Massacre of 1929, for example, hundreds of Arabs hid Jewish neighbors from Arab mobs targeting Jewish homes, protecting them from near-certain death. While the Jewish community of Hebron promptly evaporated by leaving (or having been killed, of course), this shows that there was not a unanimous existence of ethnic conflict in every person, and that there were many people who were uninvolved in the conflicts themselves on a day-to-day basis. This mirrors, in many cases, the situation that persisted following the 1967 war, when many Palestinian Arabs and Israeli Jews did cooperate economically and in some cases quite peacefully, despite the divides resulting from occupation and national disputes.

How much of the dispute pre-WWII is the fault of the desire for a Jewish state, or Jewish immigration, or is more due to the rise of antisemitism in the Middle East generally (or to the fall of the Ottoman Empire, or any number of other reasons) is something that is debated regularly. However, it would be completely wrong to say that there was no conflict between Jews and Arabs before WWII in the area that today forms Israel, because there clearly was. How widespread the animosity was appears to be debatable as well, but it clearly grew over time as the dispute between the two in national aims continued to grow and relations soured, ending in the civil war that began in November 1947 and continued as the Arab armies invaded the newly declared state of Israel in May 1948.