[On the future prospects for electric planes for short-distance flights] There is no question that this will be unbelievably complex and costly. The only reason to do it is if we think that opening niches in the U.S. (and in other countries) will be the starting point to a broader application — eventually to medium-haul flights and beyond. One does this only if we need to make deep cuts in emissions. If we do shallow decarbonization there are other options that are cheaper — more natural gas, more renewables. But shallow decarbonization doesn’t fix the climate. Only deep decarbonization fixes the climate.