have (one's) head in the clouds
To be impractical, aloof, or fanciful, often to the point of being very unhelpful or counterproductive. He has his head in the clouds while the rest of us are trying to figure out how to fix this! My daughter always has her head in the clouds as she walks home from school.
have one's head in the clouds
Fig. to be unaware of what is going on from fantasies or daydreams. "Bob, do you have your head in the clouds?" asked the teacher. She walks around all day with her head in the clouds. She must be in love.