I can tell you that over this last year, we at FedEx have had 2/3 of our crewmembers that should have retired stick around (gone to the S/O seat) just so they could get back to a window seat. This percentage came directly from our upper management.
Our company does hire a disproportionate number of retired military guys, and quite a few of those that are sticking around may be from that group (trying to get a higher percentage of A fund retirement money since they hire on around age 44-46), but I can see the same percentage of folks sticking around at the carriers that have bled their retirements in bankruptcy court.
It all bodes poorly for the hiring future at most of the Majors...