There're also a couple non-geographical angles to all this malarkey:
--Zip supposed to get the 732s before they finally get retired, a "few short years" from now, perhaps?
--Jazz sort of circumvents scope-clause restrictions from mainline and so becomes privvy to some RJs, small, medium, and maybe large too.
--Tango originally hatched while Canada3000 was still around and probably meant to undercut it. And while it didn't do it in directly --C3 having Sept.11 aftereffects as a blow it couldn't recover from-- Tango's very much still around as a hedge against new and recycled C3 entrants to the market in the East, which at the moment meaning Jetsgo, Canjet, and a slowly-Eastwardly-expanding-Westjet), and regularly seems to be engaging in price battles to make it difficult for those other guys.
--Zip is hatched,even more obviously it would appear,-- right down to also having Headquarters in Calgary for instance -- to go up against WestJet out West and do the same kind of playing around with the market and competitors that Tango does in the East.