"Mystique" must now be considered,
along with career expectations, longevity, and status and category. But at least they're using CAL's own argument--from 1991.
"The second key issue implicating the career expectations equity is the dramatic imbalance between United's jumbo and widebody-focused pre-merger fleet and Continental's fleet, which contained only a small number of widebody craft. As of the snapshot date, United had a total of 111 widebody aircraft, 76 of which were the largest, “jumbo” aircraft – Boeing 747-400s or Boeing 777s – which are the largest aircraft in either carrier's fleets and command the highest rates and best routes. Continental had only 46 widebody aircraft, of which only 20 were jumbos. Continental had no 747-400s, uniformly acknowledged to be the most desirable aircraft, see Continental-People Express at 120 (Ross 1991) (noting the “mystique factor in B-747 flying”), in its fleet.“