They didn't "flee", there was a coordinated Zionist effort to move them to Israel:
https://en.wikipedia.org/wiki/Operation_Magic_Carpet_(Yemen)
And the anti-Zionist riots were in response to the illegal occupation of Palestinian land:
https://en.wikipedia.org/wiki/1947_anti-Jewish_riots_in_Aden
None of this was even remotely on the scale of Nakba.