with (one's) head in the clouds
Having an impractical, aloof, or fanciful outlook or mindset, often to the point of being very unhelpful or counterproductive. While you're sitting there with your head in the clouds, the rest of us are trying to figure out how to fix this! It makes me nervous the way she walks home with her head in the clouds each day.
with your head in the clouds
(of a person) out of touch with reality; daydreaming.