Character development is one of the major ingredients of novel construction. In Pride and Prejudice, Elizabeth Bennet and Mr. Darcy both develop as characters. Character development is defined as the changes a character experiences over time as a result of events and experiences.
In the beginning of Pride and Prejudice, Elizabeth is, in her lighthearted and ironic way, prejudiced against superiority that cannot or will not laugh at itself and prejudiced toward an open manner that both laughs with her at other's follies and has a sad story to tell. Mr. Darcy is prejudiced against anyone he isn't predisposed toward favoring as a result of his pride of place, superiority of intellect, and inner qualities.
By the end of the novel Elizabeth has learned that her pride in her ability to judge people has been ill founded and has led her into severely damaging prejudice. Mr. Darcy has learned that his pride hinders his inner qualities from being known and has led him to prejudicially and unreasonably disfavor individuals and risk drastic consequences.
Due to the way Austen has structured Pride and Prejudice--it's nearly symmetrically structured with the hero and heroine given almost equal weight in importance, problems and solutions--the character development seen in Elizabeth and Mr. Darcy is, for all intents and purposes, equal. The one significant inequality is that Jane Austen focuses her narration through Elizabeth's life.