The author doesn't really state that he did that, but I ran the numbers, and it seems he's doing that indeed. Not sure how he came to the conclusion that 25T fuel is in the 737, as that doesn't seem to be the case. He still didn't consider the engines that would be almost completely gone weightwise, and of course the main point stands -- the 737 is a specific model, with specific tradeoffs, to handle specific cost variables, including engines and fuel. If one is considering a new design, with drastically different variables, different cost of fuel (almost 1/5th or less) different weight distribution, different acceleration capabilities, different aerodynamics (no more bulky engines at the wings), different takeoff strategies, then this kind of "what if I flipped the fuel on the 737 for a battery" approach cannot be used as proof that an idea is "ridiculous". The author comes to the fight extremely underprepared, and honestly if we all reasoned like that we'd still be in caves. I'm all for calling Elon out on things he's more vulnerable on, but the author tips his hand with shoddy work like this.