In the film Wings of Desires (dir. Wim Wenders, 1987) angels are visible by young children and, if I remember correctly, they can be sensed by the elderly. To everyone else they are invisible. The only exception is that former angels can sense their presence (e.g. Peter Falk’s character often says “I can’t see you, but I know you’re there.”). Is this depiction of angels unique to the film or does it occur elsewhere in film or literature?