OK... FEDEX and UPS are "major airlines" and Part 121 (scheduled) airline operations under the FAA's definition. So, besides the fact that one carries boxes and the other passengers and (to a lesser degree) boxes, there is, on the face, no differece. As to who gets paid more, you can click the "airline profiles" link at the top of the page to check out the pay scales. Without checking each one myself, I'd bet my $33K first year pay at UPS that there isn't a passenger carrier in business that matches the pay and benefits (taken as a whole) at either FEDEX or UPS (particularly for someone being hired today through retirement).

As to which is easier to get into, that's purely a function of who's hiring and who's not when you're applying. Ten years ago, when everyone was healthy, the cargos had to work to lure guys away from Delta and United (in most cases). Today, it's arguable that the cargos' business plans are the most stable in the industry. I would also bet that if there were another 9/11-type incident, people would quit flying again for at least awhile (and disrupt the passanger carriers businesses somewhat). However, I doubt people would quit ordering cr@p online and wanting it delivered in a day or two, so UPS/FEDEX would likely carry on as usual.

There are, of course, differences between cargo and passanger operations. A lot of cargo flies at night, especially if you're junior. But junior guys at any airline will get the less desireable schedules, whether day or night. With postal contracts and international routes, there are day flights to be had at the cargos as well. I would think it largely depends on what you like. As they say, "boxes don't b!tch."