>> will have enough batteries for 20-30 minutes of flight >Where does this number come from, exactly? It's a ballpark. Electric planes are capable of having u

>> will have enough batteries for 20-30 minutes of flight >Where does this number come from, exactly? It's a ballpark. Electric planes are capable of having up to 1 hour ([1]), but I've taken a smaller number to allow for more cargo instead of batteries - there's not much difference between 20 minutes and an hour in terms of finding a safe landing. > Also, why not circumvent these questions by using electrolysis to make zero-carbon fuel from sunlight, and just pump that the regular way? We should try almost everything. A massively parallel approach to reducing CO2 emissions has a higher chance of success. > Or ships, which can be wind powered most of the time and backed up by PV-H2 and/or beamed power in the doldrums? Same - we should try all technically-sound options. Wind, green hydrogen, biofuel, ammonia, solar, nuclear, beamed power in the doldrums. Non-practical approaches will vanish, practical will find their niches. > We can probably also use lightweight PV coatings (or beamed power) on a blimp for air travel that won't crash when power fails. (But probably only for cargo; the Hindenburg meme will probably prevent passenger interest). Somebody should try that too. 1. https://en.wikipedia.org/wiki/Pipistrel_Velis_Electro https://en.wikipedia.org/wiki/Pipistrel_Velis_Electro