castles in the air

US /ˈkæsəlz ɪn ðə ɛr/
UK /ˈkæsəlz ɪn ðə ɛr/
"castles in the air" picture
1.

zamki na piasku, mrzonki

plans or hopes that are unlikely to come true

:
He's always building castles in the air about becoming a millionaire.
Zawsze buduje zamki na piasku o zostaniu milionerem.
Don't waste your time on castles in the air; focus on achievable goals.
Nie marnuj czasu na zamki na piasku; skup się na osiągalnych celach.