The airline of her choice should be a no-brainer. You live in the city where the world's largest airline is based. AA will take you nonstop to virtually anywhere in their network from DFW. The AAdvantage program is great. You can earn miles a ton of ways (see AA forum) including grocery shopping at Tom Thumb in Dallas. Not to mention the other ways, including surveys, dining, credit cards, banking, phone service, etc. Plus, she will earn 1000 AAdvantage miles whenever she books her flight at AA.com.

I would suggest choosing the best and largest frequent flyer program from the best and largest airline, AA.