cloud-cuckoo land

A state or realm of unrealistic and idealized fancy, beyond the realms of possibility. Often preceded by "live/be in." He's always got some harebrained schemes on how to fix the world, all of them right out of cloud-cuckoo land! If Tom thinks he'll be able to live off his bad poetry, he's living in cloud-cuckoo land! Are you in cloud-cuckoo land? We'll never be able to convince a behemoth like Shmapple to invest in our tiny tech company!

Cloud Cuckoo Land

A nonexistent place of perfection, a utopia. This phrase comes from The Birds by the Greek dramatist Aristophanes, in which the birds decide to build a perfect city called Cloud Cuckoo City. Over the years “City” became “Land.”