Which is more flight attendant friendly: American Airlines or Atlas Air (major commercial or private charter)?

I would say American Airlines as they have a larger pool of FAs and probably have more programs and expertise to cater to FAs. I'd say AA is more stable.

Congratulations on your job offers. The comments about Atlas sound fair. AA does have a union, but very high seniority, so you would be on reserve for years. Even if you are in a language specified position, you could still be flying mostly domestically at AA. Some questions: what is the pay for each, how many hours are you guaranteed; where would you be based. Have not worked for either of them, but have friends at AA. I also have several friends from my current airline who went over to Atlas, and seem happy. They are all single, don't mind being away from home for days and weeks at a a time, etc. Personally, I would go for an established, US based airline.