Regardless of legacy mergers, I suspect you will see some thinning of the regional ranks.
Independence Air was once a regional with almost 115 RJ
and FRJ). Now, all the FRJ's are gone and Indy is down to barely 50 CRJ's which will likely go when Indy liquidates. So there's one less regional.
Comair has already lost 12 CRJ's and I suspect more will be cut....though it will depend on how much Comair can cut costs and how DL
's restructuring goes.
I expect Pinnacle/Mesaba to get thinned down as part of NW
's restructuring as well. Even some of XJT's ERJ's may never be transferred, but simply grounded. The only reason we haven't see more RJ
's grounded is that many of the planes are leased and the lease holders don't want the planes in the desert. Instead, low-ball bidders keep the planes afloat by undercutting other regional affiliates.
On a more positive note, some regionals will survive and grow despite the collapsing 50 seat market. They will likely lose some 50 seaters but gain more in the 70-80 seat market.