How? Well, if a girl has had enough of every man who exists, her only remaining desire could be for a man who doesn't exist at all… - Italo Calvino

To fly is the opposite of traveling: you cross a gap in space, you vanish into the void, you accept not being in a place for a duration that is itself a kind of void in time; then you reappear, in a place and in a moment with no relation to the where and when in which you vanished.

In fact the problem Leopardi is facing is speculative and metaphysical, a problem in the history of philosophy from Parmenides to Descartes and Kant: the relationship between the idea of infinity as absolute space and absolute time, and our empirical knowledge of space and time.

…we can not love or think except in fragments of time each of which goes along its own trajectory and immediately disappears.