Flying domestically is usually cheaper than driving once you get past the range of a tank of gas or two. Also, RealID isn't fully permeated yet - my state won't fully phase out non-RealIDs until 2029.
For a single person going between two major metro areas, for sure.
But a lot of the working poor have families and travel to/from places that aren't major metro areas, and this can change the math really fast.
"once you get past the range of a tank of gas or two."
This is like the folks who say flying is more carbon friendly than driving. It's wrong, you're comparing a vehicle running cost with one passenger vs a full vehicle normalized by its capacity.
No one flies 30 mi commutes.
Few drive 600+ mi empty or alone.