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'.
(..) Our kind of fare. Pricey. Hey, there. This is Ganymede, cupbearer to Zeus. And when I'm out buying wine for the lord of the skies... Maybe we should have flown commercial. Look out! Calm down. If we didn't know what we were doing... We wouldn't be licensed. They don't have eyes. (..)2013 Percy Jackson: Sea of Monsters