Castles in the air is an idiom that refers to unrealistic ideas or plans that are unlikely to be achieved. The crossword solutions for this term include DREAMING (8 letters), dreamed (7 letters), ROOKS (5 letters), DAYDREAMS (9 letters), UTOPIAS (7 letters), and DREAMS (6 letters). DREAMING and dreamed refer to the act of imagining something that is not real, while ROOKS, DAYDREAMS, UTOPIAS, and DREAMS all refer to the ideas or plans that are imagined. All of these words can be used to describe castles in the air, which is the idea of having unrealistic expectations or ambitions.