Dwellers of Aikah
Aikah means a dense bush; wood; forest; jungle, These people resided in such a place. Holy Prophet Shu'aib (علیہ السلام) was sent to this nation. They disobeyed him and were destroyed by Divine punishment.
People of Tubba'
Tubba' was the title of the king of Yemen. The necessary explanation has been given in volume seven in Surah Ad-Dukhan under [ 44:37].