0 an idea that shows a lot of imagination but is not practical: --
It was not a flight of fancy.
Perhaps that is a flight of fancy.
This is no flight of fancy.
That flight of fancy has now become a reality.
It is not a short-term flight of fancy.
We are all of us sorry for both, but to put them in the same category seems rather a flight of fancy.
I do not think that this line of thought is a flight of fancy or even just a possibility.
I doubt whether we need spend much time on that weird flight of fancy.