This situation is really little different from the first couple of flights of the season returning near-empty to Manchester from Corfu or Crete
Im really sorry to disagree as Im obviously very pro-MAN and normally agree with your analysis, but I just cant agree on that statement.
The flynas route is nothing like our Corfu, Crete or any other seasonal charter. The inbound flights could just as easily been booked up with those from the subcontinent visiting the relatives in the North West, albeit on a slightly smaller scale than the traffic going the other way. Or even Saudi's looking for cheap deals to come and watch the footy and go shopping etc. Im sorry but 6 and 19 pax on the first 2 inbounds is pitiful whichever way you try and word it, and like I say, as a pro-MAN, pains me to say it.
The Crete and Corfu charters don't normally fill up on Greeks visiting the UK before the summer rush, however.....