AA have of course been in Stansted before, what was it, 15 years ago now, with a service to Chicago.
Differences now are :
1. Maxjet/Eos have mad it a place for premium pax to know about.
2. Direct competition with Maxjet/Eos, putting the squeeze on them multiplying New York service.
3. The continuing meltdown of service standards at Heathrow, especially for premium pax.
4. Continued moving of financial offices in london eastwards from The City to Canary Wharf (it's about a 35-minute drive from Canary Wharf to Stansted for much of the day). New York is a financial destination, Chicago, Dallas and other points on AA's network are more general.
BA next ?