airy-fairy
Insubstantial or impractical; wishful, fanciful, and unrealistic. My mom always had these airy-fairy ideas of us all traveling around the world, but we never had enough money for it. I don't think you've thought through the logistics of implementing such an airy-fairy scheme.
airy-fairy
mod. insubstantial; of wishful thinking. I don’t care to hear any more of your airy-fairy ideas.