We've been thru this before. It's lower overall cost to fly the 44% more frequencies using smaller aircraft. You wind up with fewer flight attendants, a slight increase in pilot hours, but the real driver is far greater fuel efficiency. The 762 winds up looking horribly inefficient when you consider how much dead weight it can carry compared to the 321T.
It's not a new equation -- the same logic often dictated using two 727's leaving within 45 minutes of each other on ORD-LGA and DFW-LGA vs. a single frequency with a DC10.
except that you still can't grasp that AA has fewer seats flying under its new schedule than it had using 767s.
sure, costs go down but pilot time goes UP by the same amount of new frequencies. 321 pilots might make a bit less than the 767 pilots under BK but when you add back pay increases, it isn't much. further, adding 40% more frequencies offsets a major portion of the fuel burn advantage.
and again, the 767 - at least in the 300 version - can easily carry 9000 pounds of cargo per flight because that is exactly what they are doing for DL.
so the extra weight is not dead weight at all.
and DLs 763s carry twice the number of total passengers with the only difference being the lack of a FC cabin which DL doesn't believe generates the revenue necessary to cover the extra costs.
further, US DOT data for ACTUAL usage is available for US airlines and the 763 burns about 1600 gal/hr of fuel, the 762 burnt about 1400, and the 321 burns 900.
in the seat configurations that AA is using, the 321 burns slightly less fuel per seat than the 762s but MORE than the 763s that DL uses.
when you factor in the cargo that AA carried on the 762s but doesn't now but DL does on the 763s, then the argument about decreased costs simply doesn't fly... even more so considering that the 321s cost a whole lot more than the 762s.
so, let's dispense with the argument that the 321s are lower cost aircraft. they simply are not.
AA's reasoning could only have been that by adding far more frequencies, they would increase their dominance of the market esp. among high fare paying customers - but so far there is no evidence that has happened, esp. since average premium cabin fares on the transcons are not increasing at the same level as coach seats.
AA might prove in time that its strategy is working from a financial perspective but so far the evidence doesn't support it.