A pie in th sky

if an idea or plan is pie in the sky, it seems good but is not likely to be achieved 


wishful thinking, idealism- bâtir des châteaux en Espagne, utopique, illusoire 

• Those plans to set up his own business are just pie in the sky
• Our leaders need to offer more than pie in the sky when they talk about political and social issues
• She thinks her book will be a best-seller, but that's just pie in the sky.