It would probably have to be a Voyager episode since that is about the only series I watched regularly.
Back to subject.
Of all these supposed landings, Rendelshem Forest seems to have the most credibility to me. Here you have a U.S. Air Force base filled with very competent, well trained witnesses, many of whom claim that there was in fact a UFO in the forest. Unlike other instances this one can not be written off due to mental instability of the witnesses, all the witnesses were military personel and if they were incompetent they would not have been in a position to witness these events.
However, I do believe that 97% of all "alien" sightings are due to natural reasons, like deer in headlights sort of thing, people just saw light reflecting off of animal eyes and assumed it was an alien. But I don't buy this "ball lighting" theory, it's just as ludicrous as people who suggest that the light in the sky the wise men followed to Bethlehem was a UFO. The trick is getting through the fat on both ends of the scale to get to the nice, juicy center.
Please note that 98% of what I say is my opinion and/or my "version" of the facts. Most of what I say is rumor with little to no evidence to back it up, just something I picked up somewhere.