Thank you for the opportunity to help you with your question!
well, Okies and Arkies were already Americans, so they didn't migrate from one country to another. Americans are free to live anywhere inside the US. however, economic considerations can be similar, assuming your Asians or Europeans were coming for that reason. that isn't always the case.
The Okies and Arkies migrated to California, mainly southern california, because of the Great Dust bowl and job loss. They were similar because both groups were looking for a new chance. Different because America was sympethetic towards the Arkies and okies (under FDR) while the Emergency quota act of 1921 and other Acts like it had barred foreigners from entering