Nice guide to Airflow. Would be interesting to compare it to other tools like Luigi.

I'm well under 40, and happily use two spaces. I find it helps with clarity of reading for many fonts, and is worth the millisecond to double tap SPACE.

BTW, I do this mostly from Emacs, while indenting with Tabs.

ICYMI: Sensible Bash addresses this well:

https://github.com/mrzool/bash-sensible