I cant see Jet2 and Monarch scheduled doing anything but shrinking in the next few years now.
I don't think they will shrink, just we may just see the flights expand less. Both have new routes planned for 2012 anyway.
Maybe Ryanair, Monarch, EasyJet Jet2 etc will all grow this year. You never know. And also Bmibaby's pullout may have an effect on all of the airlines' routes