Realistically, you can't replace the entire global fleet on any reasonable timescale. And when climate change starts being such a problem that even politicians

Realistically, you can't replace the entire global fleet on any reasonable timescale. And when climate change starts being such a problem that even politicians can't ignore it anymore, I think we'll have much bigger fish to fry than building electric planes. Flying is a luxury, after all. Now, I think this is very neat, but I doubt we'll ever set foot on an electric plane this century.