Castles in air and Castles in the air

Castles in the air and castles in air are semantically related. in daydream topic. In some cases you can use "Castles in the air" instead the phrase "Castles in air" as a noun or an adjective, when it comes to topics like imaginary, concept.

Castles in air and castles in the air are semantically related. Sometimes you can use "Castles in air" instead the phrase "Castles in the air" as a noun or an adjective.