Do we really want more pax flying to the US via Canada and diluting our own direct flights to the States?
It seems likely this is already happening on DUB, and probably KEF too.
Air Transat fly weekly to Toronto from MAN during winter, and in Feb, according to the CAA stats, carried 1,527 pax
which was 11% down on the previous Feb, although an average load of 191 isn't too bad. The Canadian market has changed from what it was 30 years ago, while I imagine the potential business activity is very limited.
Regarding potential loss of direct TATL pax to DUB, a look at the CAA stats for MAN-DUB over the 12 months to 30 April (no figures yet for May/June), the monthly percentage increases have all been above 10% except May'15 which was up 8% on May'14. June to December increases ranged from 13% (June) to 22% in Nov. In the 4 months from Jan'16, the monthly increases have been 20% or over, with a 25% increase in March (to 86,002 pax). It would be nice to think that all the growth was attributable to more folk deciding to spend holidays or weekend breaks in Ireland and to more business traffic between the 2 cities. However, it seems highly probable that some of that growth, perhaps even a significant proportion, is due to pax routing to the US via DUB rather than on our own direct services; the attraction being lower fares, pre-US clearance, perhaps airline or aircraft preference and for those willing to take the risk of booking flights on separate tickets, no long haul APD.
Although I've not checked, I'd be surprised if flying to the US via Canada was attractive due to lower fares, but in any case, sometimes we should be careful what we wish for.