pie in the sky
US /paɪ ɪn ðə skaɪ/
UK /paɪ ɪn ðə skaɪ/
1.
an idea or plan that is pleasant to imagine but impossible to achieve
:
•
His dream of becoming a millionaire overnight is just pie in the sky.
•
The politician's promises sounded like pie in the sky to many voters.