Aunt Alexandra and Atticus are similar in that they both want to raise Jem and Scout properly, and teach them sound values. Both insist on manners and courtesy. For instance, consider the incident when Scout tells Atticus about her visit to Calpurnia's church. Atticus appears 'to enjoy' this, but Alexandra steps in to forbid Scout to go anywhere with Calpurnia again. Although Atticus doesn't agree with such a prohibition, he immediately pulls Scout up for responding rudely to her aunt.
Atticus turned his head and pinned me to the wall with his good eye. His voice was deadly: 'First, apologise to your aunt.' (chapter 14)
Atticus, like Alexandra, is quick to enforce good manners in his children, but although both he and Alexandra want to endow the children with a sense of respectability, they have different ideas on just what constitutes respectability. From Alexandra's point of view, this means that the children should have a due sense of family pride and live up to society's expectations of how they should behave according to their class and family background. This, for Alexandra, means mixing only with the right people, and not with the likes of Calpurnia, who is black, or the Cunninghams, who are of a lower class. Atticus, by contrast, wants to teach the children to accept other people no matter who they may be and what kind of background they are from. He also rates individual virtue and strength as being ultimately more important than social propriety.