When did the Arab-Israeli Conflict take place?

Answer 1

Since the Palestinians first started being called "Palestinians" in 1948. Before that, there were skirmishes with the local Arab people as far back as the 1920's.
Since the concept of "Palestinians" was invented, around the late 1940s.

Answer 2

The Arab-Israeli Conflict has its origins in the confrontation between immigrant Zionist Jews in the Mandate of Palestine and their interaction with the indigenous Arabs in the 1920s and 1930s. Before that point, the Immigration into the land had been a small trickle and Arabs were not terribly concerned. However, the Jewish immigration in the 1920s was quite large and disruptive. By the mid 1930s, both sides had developed militias which they used both to attack British colonial institutions and each other. In 1947, as UN Resolution 181 was being debated, a full-scale war erupted between the Jewish militias and the Arab militias. When Israel declared its independence in 1948, the Arab States joined in the War which caused it to be internationally recognized and called the Arab-Israeli War of 1948-9.

Therefore, if we use the terms Israeli and Palestinian retroactively to those people who would eventually identify or would be identified as Israelis or Palestinians, the conflict started during the 1920s. If we require that these terms be strictly applied, then the conflict started in 1948 when Israel declared its independence.

Answer 3

We don't know yet, as it is still a work in progress.