The irony in all of this is Sabre, which was originally AA’s homegrown system, and probably the predominant GDS used in the US (I have no data on this, just an educated guess), is the most behind in even supporting NDC at all, and what they are offering is still a pretty bad experience.
Amadeus on the other hand provides a much more integrated experience between NDC and EDIFACT content (not yet perfect, but much better than Sabre from what I’ve seen), and AA was one of their launch customers in the US market for NDC. I’m sure they are using this opportunity to increase their presence in the US. Maybe if AA gets annoyed enough with Sabre they will switch their PSS to Amadeus too.