Ok I don't remember much, it definitely had aliens in it. I remember one scene, there is a big guy and he's looking after this boy and goes into a diner to get two burgers. He gets one tiny one and one huge one, the little boy takes the big one instead of the small one(the boy may be an alien? Then the other scene I remember is a large space ship with lots of flashing lights lowering towards the ground in the desert and the boy and big guy are watching?

I wonder if you answer might be in this thread?

https://www.askmehelpdesk.com/movies/unknown-80s-movie-maybe-alien-kid-75732.html?highlight=sheriff

Thanks that's it! I have just ordored it on Amazon ;-)