Ignoring the labor issues (company and union) with that, it makes little sense from an equipment standpoint. The 50 seat RJ isn't obsolete, but there are far too many deployed right now. In fact many of the routes probably should be back in turboprops from an economic standpoint. Why would a mainline carrier that doesn't presently share the cost of owning those airplanes outside of the length of their FPD deal want to assume the cost of owning/disposing of those birds. While they're better than the 50's, you have to imagine that the same would be true of many of the 70 seaters. If the regionals were merged into mainline eliminating those scope issues, you'd have to think that the majors would trend towards 100 seat E-Jets and the upcoming C-Series so why take on the cost of getting rid of 70's as well? If a major became interested in doing this, I think they'd just put them on mainline with their pilots. They'd probably try and recoup the cost of breaking any FPD agreement through a combination of getting labor to accept lower payrates/worse workrules on the planes and by getting the manufacturers to agree to significantly lower prices for a large mainline order. The threat of displaced feed going to a competitor and hurting you has been dramatically reduced in recent years.