Books
UFOhs!: Mysteries in the Sky (Barbara Guth Worlds of Wonder Science Series for Young Readers)
UFOhs! Mysteries in the Sky is the first book to explore the strange, exciting, and unknown world of Unidentified Aerial Phenomena for kids. UFOhs! cuts through speculation and pseudo-science to describe real phenomena as observed and documented by pilots, ship captains, scientists, and ordinary men, women, and children from around the world. Playful, probing, and beautifully illustrated, UFOhs! Mysteries in the Sky prompts kids and their parents to talk about the moon, the stars, the planets, and all the things they see in the sky, and to wonder about those we can't yet explain.
See more (external link) 
https://www.amazon.com/UFOhs-Mysteries-Barbara-Science-Readers/dp/0826364950/