Kevin,
DL is increasing MAINLINE capacity across its system by more than 5% while reducing regional carrier capacity by 2% and has been doing it all year long.
http://finance.yahoo.com/news/delta-reports-financial-operating-performance-130500378.html
DL has also done the same thing for the past several years. Even the RJ capacity that is being added is coming with more efficient, larger aircraft that have lower CASMs.
DL is doing EXACTLY what WN is doing compared to FL's strategy which is to upgauge flights in order to increase efficiency and lower costs. the only difference is that DL is doing it between regional and mainline while WN only has the mainline component to work with. What DL and WN do share is a willingness to acquire used aircraft because of the lower capital costs involved. AA and UA are getting rid of some small RJs and replacing them with large RJS but they are acquiring all of their aircraft - RJ or mainline - as new and in AA's case, the addition of the 319 is actually downsizing many flights. Larger aircraft generally mean greater efficiency and lower CASM. You can tell me the normal staffing between a 717 and 739ER or 753 but I can assure you that DL like WN is using larger aircraft to increase efficiency and reduce costs.
but the entire system is increasing, particularly in terms of the number of mainline flights - which means more staffing.
It is not a red herring to note that SLC just had to be PROPERLY staffed for additional flights to create additional jobs for DL people.
the INCREMENTAL revenue for DL by adding one more mainline flight is far greater than the incremental costs of staffing that flight.
and Josh's point is valid... if UA has no in-house cargo personnel, DL has to staff its cargo operation based on industry standard costs. IF UA now has far lower cargo costs because of outsourcing then DL's costs get shifted form cargo to ramp personnel.
look at the big picture of what is going on at the company overall including at SLC and it will make sense.