I checked the fares on both of the airlines referred to in the Times Online article (Zoom and Canadian Affair). They are, on average, a few hundred dollars cheaper than regularly scheduled carriers.

However, anyone thinking of booking on either of these, should do so soon. For example, Zoom has already closed some of its Toronto-Glasgow and Toronto-Gatwick flights for May. Seats are selling quickly.

Lucy, (trying to organize our May trip to Ireland) Toronto