So, looking at the graph as a whole the lower right is considerably more busy than the top-left. One interpretation is it appears parents in the US are much more willing to give traditionally "male names" to girls. That empty top-left is interesting too. You may argue that almost no one is giving boys a traditionally "female name" on either side of the pond. Obviously other interpretations are possible too!

Wendover has a good video on how airlines have essentially become banks. Miles are the currency.

Delta exists so that SkyMiles can make billions of dollars. It's where the money is now. $2B to $3B a year net profit from what I could find.