Comment by feyman_r

>> Why were other airlines able to get back to normal so much faster than Delta?

I read somewhere that their crew tracking software was hit hard and took time to recover. Will look for source on that.

(Edited) source: https://news.delta.com/update-delta-customers-ceo-ed-bastian

“… and in particular one of our crew tracking-related tools was affected and unable to effectively process the unprecedented number of changes triggered by the system shutdown…”