In the clouds是一个常见的表达，用来形容某人或某事物的思想或情绪不现实或不切实际。例如：

She's always in the clouds, thinking about her next vacation.
His ideas for the company are always in the clouds. They're not practical or feasible.

也可以用in cloud cuckoo land来表示同样的意思。例如：

He's pving in cloud cuckoo land if he thinks he can make a fortune selpng that product.
She's always in cloud cuckoo land, dreaming about winning the lottery.