Something working for rockets doesn't mean it will work for planes. The physics are very different, and rockets can use inefficient and scarce fuels because the

Something working for rockets doesn't mean it will work for planes. The physics are very different, and rockets can use inefficient and scarce fuels because there are relatively few rocket launches and they carry high-value payloads. Also, the idea that renewables will bring energy abundance is based on a shallow economic analysis that ignores material factors.