Casablanca

The film uses Casablanca as its running argument about love. On their first drive Harry and Sally fight over whether Ilsa was right to get on the plane, and years later they watch the ending together over the phone from separate apartments. It is a reference the characters make, and the question it poses, whether you settle for the sensible choice, is the film's own.

Han Solo is Rick Blaine in space: the cynic with a debt, a bar, and a refusal to pick a side that lasts exactly until the third act. Lucas has cited the film among his sources, and the cantina is the scene that makes the borrowing hard to miss.