I would not at all be surprised if there was truth to what Sagan is saying but I feel like he is touching at something much much bigger. Iirc alien abduction stories often also share characteristics with general recalling of religious experiences. Something about the American psyche jumps to aliens when that pineal gland is getting tickled, seems like.

(Perhaps some day Americans will have culture and its religious backdrop is gonna be all cryptids and aliens and it will be much cooler than evangelicals or Mormons)