To define Charlotte Brontë's opinions with regard to social classes, look to the characters in her novel, Jane Eyre, and her opinions regarding the three things that the book focuses on: "education, women's employment an marriage."
Discussion of the classes arises in the way people were educated at the time. Schooling young men was a long-standing tradition. For many years, women were educated in a much less serious manner, and even then, based upon one's social standing. For many years, the poor were never educated, but by this time, all children were schooled, though the poorer class was given a "cursory" education which lasted only until they left to take jobs or join the military service.
For the emerging middle class, as well as the upper-class, education was much more refined, though still a more serious prospect for men than for women. Children when still quite young, would be taught by a governess—the job Jane takes when she leaves Lowood Institution. When boys were of the proper age, they would be sent to boarding school and/or to private school. ( Private schools were, confusingly, called "public schools"). Public schooling led to schooling on the university level, something not available to women until the 1870s.
Marriage is also something in the novel that speaks to Victorian expectations, based on social class. The most realistic marriage is the one that comes under discussion between Edward and Blanche. Bertha and Edward marry not because they are socially suited: she was a dancer, but became pregnant, ostensibly, with Edward's child. Realistically, it would be more unusual (but not unheard of) for Edward and Jane to marry. Jane, after all, is a governess, and beneath Edward's station in life.
In terms of employment, there were little opportunities for women. The first, and most acceptable manner in which a woman survived in society (in an acceptable way) was through marriage. Barring that, she could become a governess—a station in which a woman was considered a little better than poor. These women hovered somewhere between the two classes, with little hope of improvement, unless married—but not to someone of the upper classes. (At this time, office clerks were men!)
More than just a love story, eNotes states:
Jane Eyre is not only a love story: It is also a plea for the recognition of the individual's worth.
With all these things in mind, we can infer several things: Brontë saw the value of the individual over the value of one's place within society. We can infer, too, that Brontë herself was something of a rebel. She was unmarried in her early years as a writer, and was an educated woman who believed that while there were social limitations placed upon one based on background, gender, learning, and social standing, one could improve her lot in life. Even after marriage (though she died very young), Charlotte Brontë continued to write, defying the generally accepted expectation of women in society, on all social levels: marry and raise a family.
As seen in Jane Eyre, Edward and his upper-class guests at Thornfield are lacking in character, wishing only to "play." They have little regard for the lower classes—servants...and especially governesses. Members of the middle class often lived comfortable lives (as seen with Jane's Aunt Reed and her cousins), but Jane seemed to expect that they, as the more fortunate, were responsible to help others.
Jane's ideas, we can infer, were Brontë's ideas.