Oxera conclude that that the most intuitive deduction about economic impacts, taking the Airports Commission’s traffic forecast as given, is that Heathrow expansion would be more likely to exacerbate rather than mitigate regional imbalances, by drawing more business into the London area
Thank you for highlighting that. My own particular interest is MAN and I've expressed concern that an expanded Heathrow with all those extra slots could reduce our rate of growth and even cause our long haul services to stagnate or even reduce. It amazes me that some of our local MPs for example have accepted the premise and assertion that a third runway at LHR will only improve connectivity and benefit the regions. New domestic flights to LHR from say LPL or DTV may help them but doesn't do much for MAN.
So I think it is right for the report to suggest that the impact will vary from region to region and airport to airport. As for BHX, I suspect it is the fact that you are that much closer to LHR that could adversely affect you if greater frequency of flights and more destinations become available at LHR.
It depends what Davies eventually recommends and what's in the detailed report by way of evidence, reasoning, analysis etc. but some of his comments so far regarding regional airports have hardly been encouraging.