I remember reading a short chapter book when I was a kid. Here's the story: Boy lives on a farm. The boy meets an alien. Another alien, the alien's rival (of some sort) tries to take him away because he knows aliens exist. At some point, the following things happen in the plot:
One alien or the other dismantles the old barn on the farm.
The alien's rival makes it impossible for his parents to believe him about there being aliens. When the rival alien tries to kidnap the boy, he is quickly set down outside so his mother doesn't see him being lifted into the air. He is set down in another place, and walks back into the house to tell his mother he was almost kidnapped, and points to the footprints in the snow as proof. She smiles and says he just walked backward through his footprints.
It's possible that the book had a title something like "Dan in space" or "Duncan and the alien". Probably published in the late 1970's, given what my school district could afford.