Tennessee Williams's The Glass Menagerie has many themes, and one of them certainly concerns what is known as the "American dream." This is the belief that in America one should be able to do or be anything. In this play, many characters fail to live up to their potential, but only one is bold enough to take any real action toward his goal.
Amanda is a southern lady who finds herself as single working mother struggling to make ends meet. She has two jobs and is able, with Tom's help, to provide for her family. This is not what she envisioned as her the American dream. In her world, gentlemen callers come to visit, daughters make suitable marriages, and all material needs are met. None of that happens for Amanda in the end.
Laura is a fragile girl who is certainly bright enough to learn a skill and have a career, but she doesn't have the temperament to do so. She will probably never marry and achieve anything through that relationship; nor will she find satisfaction in any kind of work. Laura will live her life essentially unfulfilled. No American dream for her.
Jim talks as if he's actually going to be what he sees himself being one day, but his reality is far less productive. He had everything going for him in high school, but years later he's simply another warehouse worker who has hopes for something bigger than he will probably achieve. His American dream is not particularly fruitful.
Tom is the only one who is utterly dissatisfied with his life. He's weary of his demanding (and annoying) mother; he's weary of working in a warehouse; he's weary of getting little personal benefit from his earnings; he's weary of having to "hide" his creativity; and he's weary of staying where he has always been. He wants nothing more than to escape, to travel, to write, and to be free. That's his dream. At the expense of the people he loves, he does pursue that dream. He does escape, he does travel, we presume he is able to write--but we're fairly certain he's not really free. In the final scene of the play, as Laura blows out the candles, Tom is still connected to his past and we know he will never be totally free. His American dreamhas only partially come to fruition.