Electric air transport is unlikely to happen for commercial transport.
If you replaced 5500 kilograms of fuel with 5500 kilograms of modern batteries, you would need an improvement in battery efficiency of around 20 times. Batteries increase in small % over decades, not by magnitudes.
Essentially, you would need batteries that store 20 times as much energy as the best technology does now at the same weight and density.
And there's another catch: airplanes burn less fuel as they travel, because burning tons of fuel make them lighter. So it's not really a 1:1 comparison and you likely need more than 20 times to compensate.
There's other catches: cooling such batteries would be an engineering nightmare, but safety would be another concern.
There's a twist though that even more so than cars, torque-on-demand is extremely important to airplanes. It's part of why airplanes always carry more fuel than they need for their destination, because when you need extra torque you burn the fuel as fast as possible to get that torque.
So there are airplane manufacturers exceedingly interested in battery planes because electric propellers and even potentially some electric air jet engines benefit from wild efficiencies when purely electric, and are safer at high voltage torque demand that batteries can offer more than traditional "hope you can burn enough fuel fast enough for the emergency torque need".
Those battery versus fuel trade-offs are enough that right now we're only seeing those electric efficiencies and safety improvements in the low end (the modern "drone renaissance", and a few select small private/personal plane manufacturers). There probably will need to be a surprise innovation to see it in larger planes and commercial transport, but it's also starting to seem a lot less "impossible" the more small planes that are entirely electric.
Just a nitpick - to make anything CO2 neutral, including planes, we need to remove the same amount of CO2 from the atmosphere as had been emitted during construction and usage of that thing (a plane or anything else). This is not happening any time soon.
The better name would be "Green" or "Eco-friendly" flight, because "CO2 zero" or "CO2 neutral" is impossible for us yet.
If you replaced 5500 kilograms of fuel with 5500 kilograms of modern batteries, you would need an improvement in battery efficiency of around 20 times. Batteries increase in small % over decades, not by magnitudes.
Essentially, you would need batteries that store 20 times as much energy as the best technology does now at the same weight and density.
And there's another catch: airplanes burn less fuel as they travel, because burning tons of fuel make them lighter. So it's not really a 1:1 comparison and you likely need more than 20 times to compensate.
There's other catches: cooling such batteries would be an engineering nightmare, but safety would be another concern.