Sayid's electrical map reveals two interesting features of the Others camp: two underground passages that seem to lead far beyond the protected perimeter.
Claire's aunt Lindsey was the woman visited by a drunk Christian Shepard during his trip in Australia in Two for the Road (2006).
The title of this episode ("Par Avion") literally means "by plane" in French, and commonly refers to "air mail," which is used on letters to indicate to the post office that they are traveling overseas.