Davies & Regional Long Haul
Manfod
Davies wasn't critical of regional long haul as such. His comments on environmental issues were in the context of measures to encourage greater use of regional airports through policy levers such as differential APD. His number crunchers indicated that such policy levers would increase the numbers of long haul pax at regional airports, with a similar reduction at Heathrow (and Gatwick). However, the spreading of pax across airports would result in an increase in the numbers of flights (ie a reduction in average loads), presumably through the use of smaller aircraft at regional airports (not just Manchester, of course). Therefore, emissions per pax might be expected to rise.
It seems a pretty weak argument to me, as you could turn the argument around to say that there should be no long haul flights at all from regional airports and that we should all fly on full A380s from London...
Interestingly, the Davies analysis suggested that MAN would not the main beneficiary of such policy levers, with smaller regional airports getting the bulk of the increase in pax. However, his methodology is not at all clear, and I would question his conclusions in this respect.