I noticed that there are several Esperanto references in the British sci-fi series Red Dwarf: by the lifts the level is written as Nivelo, and one of the main characters keeps trying (with little success it seems) to teach himself Esperanto.
I'm also aware of Incubus (1966), which I believe is not a SciFi film, but uses Esperanto to create an atmosphere of strangeness.
Are there any other examples where Esperanto is used, presumably under the assumption that in the distant future Zamenhof's aim of a single language to further peaceful co-existence has been achieved?