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We Still Have No Idea How To Eliminate More Than a Quarter of Energy Emissions (technologyreview.com)
Climate discussions typically center on the need to replace fossil-fuel power plants with technologies like wind turbines and solar panels. But a new paper in Science offers a stark reminder that there are still huge parts of the global energy system where we simply don't have affordable ways of halting greenhouse-gas emissions. MIT Technology Review: Air travel, long-distance transportation and shipping, steel and cement manufacturing, and remaining parts of the power sector account for 27 percent of global emissions from the energy and industrial sectors. And the authors say we need much more research, innovation, and strategic coordination to clean up these sources. "If we're really ambitious about meeting our climate targets, we need to be tackling these hard sectors now," says the paper's lead author, Steven Davis, an earth system scientist at the University of California, Irvine.
The absolute best batteries available today are around 1.8 MJ/kg in storage. Compare that with jet fuel which is around 43 MJ/kg. Now cut the range your airplane can fly by a factor of (43/1.8) ~24 and you'll see the issue.
That is not a fair comparison. A battery can convert 95% of its energy to thrust. The best turbofan jets can reach about 36%. So ((43 * 0.36)/(1.8 * 0.95)) = ~ 9.
But that isn't fair either, because when you burn fuel you are no longer carrying the fuel, so the plane gets lighter and uses less fuel per mile further into the journey. The weight of a battery doesn't change. The batteries are deadweight during landing, making landings more dangerous and requiring longer runways.
Batteries need to improve by a roughly a factor of ten to be competitive for long haul aviation. That is unlikely.
A compromise may be to use electrical energy for the takeoff, possibly with a mass driver with the batteries on the ground. This means smaller, quieter, and safer jets (since they don't have to be beefed up for takeoff thrust) as well as shorter runways.