It is also important to know that based on the last two quarters of financial results, AA has maintained a 15% cost disadvantage to CO and DL and an 8% cost disadvantage to UA.
AA's cost disadvantage is even more pronounced relative to low fare carriers such as AS and B6 which have significant overlap with AA. (even though AS is a codeshare partner, AS and AA are legally still competitors because US domestic carriers cannot cooperate on revenue or cost generation as AA can now do with BA etc).
While AA mgmt is counting on an increase in costs by UA and CO as part of their merger, there is no large scale cost increase on the horizon by DL.
Keep in mind that the quote you are providing is based on the tentative agreements which have been reached. There is no tentative agreement with some of the most costly labor groups. AMR mgmt knows that the pattern they set for agreements with one group will be carried through to other groups. The 0.15 cent cost increase could easily become 3-4 times that amount or more when it is spread to all labor groups... and it comes on top of AA's labor costs which are already the highest in the US industry.
If 0.15 cents per ASM was all that AA could expect to see labor costs increase, they would have signed the contracts a long time ago.