All their children have 'flown the coop'. [=have moved away from home]
Her books are filled with abstract ideas and 'high-flown' language.
In the morning the suspect had 'flown the coop'.
(..) At this time of the year Yet they gather in some numbers on these apparently barren slopes. They're searching for a rather unusual food - moths. Millions have flown up here to escape the heat of the lowlands and they're now roosting among the rocks. Moths may seem a meager meal for a bear, (..)2006 TvShow: Planet Earth Title: Mountains Season: 1 Episode 2