Jim

Jim: "And everybody has problems, not just you, but practically everybody has got some problems. You think of yourself as having the only problems, as being the only one who is disappointed. But just look around you and you will see lots of people as disappointed as you are."
The Glass Menagerie, Scene 7, pg. 1277

"In what ways and in what sense is Jim more "realistic" than the Wingfields? Does that mean that he is without delusions? Of what is he symbolic?

I think that Jim was more realistic that the Wingfields because his words and thoughts were actually rational. Jim had ambitions that were attainable, whereas Tom had ambitions that didn't have an actual goal.  Jim also showed genuine feelings toward others. He was the only one to tell Laura that she was beautiful, that she had worth, and that she should not be so shy because she has many redeeming qualities. He is the only character that was able to plant an ounce of confidence within her. I don't think that Jim was delusional. He was realistic and he knew what he was talking about. At the beginning of the play he was considered to be a symbol of that long-delayed but always expected something we live for. This describes Jim perfectly. Without Jim's appearance in the play, the reality of the Wingfield's lives would not have been recognized by the Wingfield's. Jim was able to demonstrate to them that they were indeed living in a world of illusions. It seems that Jim's visit prompted Amanda to believe that maybe Laura would be single her entire life-but that would be okay; it seemed to have prompted Tom to take the initiative to finally leave home and pursue something larger than his current life; lastly Jim showed Laura that she should think more highly of herself. Although he left the dinner abruptly after announcing that he was engaged, I think that this revelation was still good for the family. Not everything is going to turn out like it's supposed to. Jim is able to portray this to the family. They can only hope for the best. Jim is the realistic character that altered the Wingfield's views on their life; he is the change that they had all been waiting for, even though they didn't realize it.