I read this in the late 1970s. A 12ish year old boy living in a rural area of the US notices small lakes are disappearing in his area. He deduces that aliens are stealing the water to use for fuel and starts watching for their ship, which he boards when he sees it. The ship takes off while he is aboard and the rest of the book is his adventures in trying to return home. There are other abductees from other planets already on board who become his crew. It is a loose re-telling of Homer’s The Odyssey in that the boy travels from planet to planet aboard the ship and encounters people who are recognizably the Lotus-Eaters, the Cyclops, Circe, etc. Because it’s a children’s book, many of the details are toned down. For example, the Cyclops had poor vision and thus needed to wear a thick lens to see, which the adventurers broke to “blind” him. I remember very well there was a full-page painting of the boy in the Cyclops cave, which might have been the cover of the book.