While the Ford Model A was discontinued in 1931, it was still incredibly popular during the 1930s, and its used models accounted for a significant portion of car sales.
For new car sales in 1939, the top spot is a bit more contested. The top contenders were:
* Chevrolet
* Ford
* Plymouth
It is difficult to say definitively which one was the absolute top seller for that year as manufacturers did not publicly disclose their sales figures in a standardized way at the time.