The thing I quoted is more for bigger jets with much larger engines (it was the first reasonable looking source I found). In any case their hybrid has four engi

The thing I quoted is more for bigger jets with much larger engines (it was the first reasonable looking source I found). In any case their hybrid has four engines, two electric, two conventional, so you are really should think of it as needing to haul two extra engines on top of what a conventional only jet would have.