World, you have stressed repeatedly that AA's unprecedented aircraft order may be more airplanes than AA can afford to buy and remain profitable. I've argued that the fuel cost savings at today's prices pays the lease on the MD-80 replacements, and they're the bulk of the new plane orders. DL and UA are also beginning to retire their 757s, just like AA, so that's a wash. DL certainly has an advantage by grabbing most all the available MD-90s and 717s, but since the supply of those is about dried up, the only viable alternative is new fuel efficient planes.
One thing is for sure, however, and it's that AA's investment in new planes helps AA (and Boeing and Airbus) but doesn't lower the costs for DL or UA. AA is able to garner all of the fuel savings from that investment and keep those savings within AA.
Delta's altruistic gesture of buying, refurbishing and operating a refinery has helped Delta but Delta wasn't able to prevent every other buyer of jet fuel from seeing lower prices in the NYC area. That helps not only UA and AA, both of which buy a lot of fuel in the NYC area, but it also helps B6, VX and WN, all of which are pretty big (and.or getting bigger) in the NYC area. Last, Delta's refinery, if it indeed has caused lower jet fuel prices in the NYC area, also helps all the foreign airlines at JFK and EWR, by lowering the cost of their return trips.
It's the same as if one farmer spent money to improve the grass production in the common green - all farmers would get the benefit of more milk from their now-fatter cows grazing on that common green, but only one of the farmers is footing the bill for the irrigation/fertilizer/etc that is causing the increased grass production. That one farmer - is Delta. Nice of Ma Delta to lend such a helping hand to everyone.