I think investing in [existing tried and true technology that powers the whole world outside a bubble] makes little sense. We should invest in [technology that doesn't exist but could possibly be applied in roughly the same space for many times the cost].
It's impossible for electric planes to be cheaper than electric rail - everything about a plane is harder to achieve, the size will be smaller (since it also needs to lift off the ground, not just drive), safety is a much bigger concern (leading to much more time for boarding procedures). The only advantage air travel has is that it doesn't require real-estate.
Instead, electric planes still need decades of engineering work, and what we know for sure is that they will be less efficient than kerosene planes, as there is no type of battery even plausible today that could achieve anywhere near the energy density of gasoline (in Wh/kg, not Wh/l as is sometimes shown).
Your logic would imply that it's impossible for conventional planes to be cheaper than conventional rail, which is definitely not always the case in the US.
What are we talking about here? Passenger fare? That's almost entirely abstracted away from actual cost of installation because it's in large part driven by demand not supply.
Infrastructure cost? New railway projects are notoriously expensive, but so are new airports.
Per unit cost? Train locomotives and carriages are far cheaper than planes.
Operating cost? Trains are far cheaper over time than planes. Their maintenance is far less intensive, they can run on just about anything, and they last for many decades without issue
Many small and medium under utilized airports already exist.
Many regions where it would not make sense economically to connect high speed trains can be connected with electric plains. For many regions you simply don't need more then a small number flights.
Trains make sense when you need transport very large numbers of people.
Airplanes can be dynamically allocated where needed much easier.
And the simply fact is, despite massively subsidized rail infrastructure, even current planes are the cheaper option. Electric trains will require far less maintenance and will use electricity.
Legally speaking building a train line across developed region is an absolute nightmare. It takes a very long time, often isn't successful at all and the project takes so long that financing interest is a killer.
Comparatively a really quite electric plane is easy, far easier then current planes.
The far faster speed of planes is preferable to most people. Sure there are super fast trains, but those are really only viable on a incredibly small set of routes.
It's impossible for electric planes to be cheaper than electric rail - everything about a plane is harder to achieve, the size will be smaller (since it also needs to lift off the ground, not just drive), safety is a much bigger concern (leading to much more time for boarding procedures). The only advantage air travel has is that it doesn't require real-estate.
Instead, electric planes still need decades of engineering work, and what we know for sure is that they will be less efficient than kerosene planes, as there is no type of battery even plausible today that could achieve anywhere near the energy density of gasoline (in Wh/kg, not Wh/l as is sometimes shown).