What did Vladek think Hitler wanted in Maus?

In chapter 2 of Maus, Vladek is telling the story of his life with his wife, Anja, before the start of World War II. At the time, Vladek was running a successful textile factory in Bielsko, Poland. While running the factory, the town was stirred up in fervor against the Jews—to the point that there were riots downtown to get rid of Jews in the city.
As a result, Anja and Vladek talk about leaving Bielsko and moving back to Sosnowiec, where Anja’s parents live. Again in the frame story, Art asks his father why they would move back to Sosnowiec—it seemed just as dangerous for them as Bielsko. Vladek answers and tells him that

We thought then that Hitler only wanted the parts from Poland, like Bielsko, that used to be parts from Germany before the first world war (39).

Vladek’s explanation helps us understand that the Jews at the time might not have understood the full plan of Germany. That is why they didn’t move very far away—if Vladek and his family had known what Germany and the Nazis would do, they would have probably moved somewhere safe. They had a lot of money and the ability to move at the time but didn't know the extent of the danger.