Spirit has Atlanta to Dallas round trip for $61 on an 8am flight according to Google. That’s not much more than I paid on a last minute booking in Germany. To drive it would be an 800+ (~1300km) mile trip my my house North of Atlanta to Dallas and take 12 hours no stops.

What trips in Europe are 1300km and how long is that train ride?

I would love an Atlanta to Raleigh or Atlanta to Savannah train but I think your comparison is kinda extreme. A better comparison would be Atlanta to Athens/Columbus/Chattanooga.