I am searching for a science fiction story I read years ago (I guess around 2000). I was part of an SF-Short-Story-Collection (Isaac Asimov's Magazine or the Heyne-Almanach [example]) and was published translated in German in Germany. The story is about an alien invasion. The strange thing is that the aliens love the airstream globetrotter (the silver Caravan) - they are really mad about them.
Another Thing I remember is that the only people which can communicate with the Aliens suffer from trisomy 21 (Down Syndrome).