Thanks, kk -- I do fly on delta when travel in the US, when I go where they're going. Especially coast to coast on Delta One. Haven't explored delta international yet because I typically go to Hong Kong. Will be doing some European travel when this nonsense is over. IF! As long as I get there on business or first class, I don't care what airline I use.

"...suboptimal earnings..."
This is where I'm a newbie. Ready to learn.
Why would they be sub-optimal? The only other option I've seen is 2% cash back. What would be optimal?