In the 1940s and 1950s, pan arabism grew in the middle east in response

We can talk about two main reasons for boosting pan Arabism in the regions of North Africa and the Middle East:

The creation of the state of Israel in 1948, was seen in the Arab world as a betrayal from Western powers. An also created as an outpost to the influence of North America.

In the Arab world, leaders as Nasser in Egypt started to unite all common nations with an Arabic origin, not only basing on religion, (as in pan Islamism).  The pan Arabism doctrines proposed socialist demands. In the 1950s, Nasser strongly opposed Western political intervention in the Arab world. It also sought to empower Arab states against outside forces by forming a great Arab alliance and also considering a special form of economic co-operation.