I could be wrong, but as I understand it, it’s the other way around—UAL is reducing its use of UAX because it is upgauging by buying all those narrow bodies. Either way, the policy seems sound—a full 737 should have a lower CASM than an RJ on the same route (much like, as Andy noted in a post above, widebodies have lower CASMs than narrowbodies).

The good news about narrowbodies is that, during a downturn, they can still be redeployed effectively. With limited international and/or business travel (also as noted in another post above), widebodies can quickly become really expensive paperweights.

Regarding staffing, one does wonder how they’ll be able to staff their jets.