Is there any evidence that's what happened? As far as I can tell, the NSA was doing it's routine thing of spying on foreign governments and and discovered that Airbus was trying to bribe a gov official.

Maybe you agree with Henry L. Stimson that "Gentlemen do not read each other's mail", but I haven't seen anything indicating that the NSA was spying on behalf of Boeing, or even directly targeting Airbus. Maybe I missed something, would be happy to learn if you have any sources to share :)