Will the Real Mr. Howell Please Stand Up? - S2-E26
Continuity mistake: After building a sandcastle, Gilligan goes to talk with Mr. and Mrs. Howell. When the three go to the spot where the sandcastle was, it is gone. Instead, there is a log, which Gilligan trips over.
Will the Real Mr. Howell Please Stand Up? - S2-E26
Revealing mistake: When Gilligan demonstrates his man-made wings, when the camera goes close up to him, you can see the wires.
Answer: Bob Denver answered this when he was on a talk show hosted by Pat Sajak. He said they were going to write into an episode where the castaways found all these clothes, but it got too complicated, so he said, they decided, "who cares, it's only a TV show," and forgot about it. So the writers and actors even asked this, they just never bothered to address it.