[lupusreal]

That's a lot of handwaving but the reality works out to jet fuel being orders of magnitude more efficient than batteries on the basis of how much of either you can get into an airplane and how far they will take you. One key factor is a load of jet fuel gets much lighter as you burn it, but batteries don't get lighter as you drain them.

[jmward01]

One thing I have been thinking about for electric is how it may allow completely different flight possibilities that could leap ahead of what we have now. For example, extremely high altitude flight is a huge challenge for current aircraft on a number of fronts, but a big one is how do you design an engine that can produce power at extreme altitudes. The higher you go the more heat limited you are in a gas turbine engine. Electric doesn't have that issue so it may be able to push aircraft a lot higher which would enable faster/further travel for far less energy use. The energy density comparison is predicated on using that energy in exactly the same way with the same efficiencies. If long distance flight becomes 100x more efficient then the density difference isn't a problem.