Why?

Planes are faster, and there is actual competition keeping prices down. There is no competition on railroads, no accountability, no nothing. More importantly, railroads have to be managed centrally to work. And this makes them overwhelmingly complex, resulting in an ever-growing bureaucracy.

Air travel is decentralized, and while individual airports (cue: BER) can get screwed up, it doesn't cascade through the whole system.

We just need to add a bit of carbon pricing to reflect the true price of flights.