It's worth noting that MHT airline operations have declined dramatically since the latest round of industry consolidation began. Departures declined 45 percent 2007-2012; passengers down 37 percent 2005-2011.
http://www.unionleader.com/article/2...887&source=RSS
This is somewhat because the "Southwest effect" (that drove the initial boom at MHT, and major airport expansion) has been blunted, partly by Southwest opening BOS as well, also because Southwest isn't such a low-price leader any more in general. It's also owing to mergers, and airlines cutting back in marginal markets. NW opened MSP-MHT before it was merged away, and DL operated CVG-MHT. United used to have mainline service to ORD. Those flights and many more are gone now, and MHT has hardly any mainline service outside of the Southwest 737s.
It's almost all Barbie jets, and as you wander the deserted, unused concourses with the blank gate screens and jetways gathering dust, it's sad to think about the boom this airport was built for that has now died off thanks in part to the mergers.
PWM is in similar straits. The airport was expanded within the last ten years but today it looks like a huge misstep. Last time I landed there in a DL RJ, at mid-morning, we were literally the only commercial aircraft on the field.
BTV has always struggled.
My point is that I think it's incredibly wishful thinking, perhaps naive, to imagine that AA/US would lead to more flights out of underserved airports like these, or that UA would respond with more service. As we all know, UA thinks the road to success is with less service, less capacity... and the evidence in general is that mergers don't lead to more flights to more places, they lead to less.
I take an interest in northern New England air service (AA doesn't)... I used to live there and still fly back a lot. MHT used to represent a major price advantage versus BOS, like BWI over DCA. Not anymore.