When Kimberly Bermudez got off her Southwest Airlines flight to Jacksonville, she was $530 richer, but the money isn't for her — it's for the first-graders she teaches at a low-income elementary school in Chicago. While chatting with the passenger next to her last week, Bermudez shared the challenges of being a teacher at a school where some kids come to school hungry and others are homeless, but also the joy they bring her.