I would guess a considerable percentage because launching and landing takes a disproportional amount of power. Iirc their information correctly then launching a

I would guess a considerable percentage because launching and landing takes a disproportional amount of power. Iirc their information correctly then launching and landing takes 10x as much power as level flight. That's because in these situations lift has to be generated by the fans instead of the wings. So short flights are actually disadvantageous.