last I checked JB was listed as a national, not a legacy/major? of course that all depends on what criteria you are using when you say major... if you are using the revenue standard, there are many airlines operating regional equipment that meet the money threshold as a major...

so, is the question who is the worst paying airline operating mainline aircraft? That would be RAH, their wonderful contract allows them to operate the EMB-190/195 at regional work rules and regional pay... a new record in lowering the bar.

If yo limit it to Boeing and Airbus you may get some more answeres in line with what you are looking for.... since the word "Major" no longer has a definition in our industry.