Atterraggio literally means "landing", as in an airplane landing. It's an interesting word because it evokes a sense of caution and planning.
In the song, Laura Pausini uses it metaphorically when she sings, "Valutavo l'atterraggio prima di partire" (I was evaluating the landing before taking off). This line powerfully conveys the idea of overthinking and being held back by fear of failure, even before starting something new. It's a unique way to express hesitation and a desire for security.
"Zero" is Laura Pausini's refusal to settle for feeling nothing.
She opens by admitting the fear that used to hold her back: the fear of the unknown, of a sudden change of wind, of taking flight at all. She hid her wild side for so long she almost forgot it existed. Now she's done playing it safe.
The chorus is a demand, not a wish: give her anything except zero. Calm or storm, it doesn't matter which, as long as it's real enough to leave her breathless. She's done waiting in defense, and she's taking back every moment she once let slip by, without asking anyone's permission.
By the end, she's found the courage she didn't know she had, still refusing to accept less than everything.