Comment Re:Silly. (Score 2) 73
Even if battery energy density started getting close to that of liquid hydrocarbons, and thats a looong way off still, youd still need more batteries than you would fuel because batteries dont get lighter as they discharge like burned fuel does, rocket equation stuff. A 747 carries ~150k kilograms of fuel, if that didnt burn off thats an extra 37k kg the first quarter of the flight, an extra 75k kg the first half of the flight and so on...
Battery planes may never make widespread sense, if we ever start generating enough carbon free energy cheaply enough and even if all ground transport goes battery electric or whatever, at some point it might still be worth it to just make carbon neutral jet fuel with air fuel synthesis. That seems closer on the horizon than the battery tech needed for large planes to be feasible, hard to beat jet turbines for that application.