I think your comment(s) on how each regional will be impacted-and therefore each major (depending on exposure)- is an interesting question to look at.
In a past lifetime, I worked for YV on the UAX side. This was during the hiring boom of the mid '90's, and we were losing pilots left & right to the majors, and it had a huge impact on our operation, which in turn impacted UA's...
that is exactly the issue which E raised, which I responded to by saying that DL's 717 deal and CRJ flush, and AA's BK pilot contracts which allow AA to put lots of new large RJs into service gives AA and DL an advantage. UA is far behind.