When Hi, Gale and Evelle are sitting in the trailer talking about robbing the bank, watch the newspaper on Hi's lap. It goes from being folded to being fully opened in his hands between shots.
In several scenes where H.I. is in the factory where he works his work suit has a "Hudsucker Industries" patch on it. The Cohen brothers who directed and produced the movie also put out a movie a few years back called "The Hudsucker Proxy."