A quick review of the ORD schedule shows at least 32 daily MD-80 flights to the West Coast (including Arizona and Las Vegas), averaging over 1,500 miles. AA recently said that a typical MD-80 flight DFW-LGA burns about 880 gallons more than would a 738. These ORD flights thus burn about 1,000 gallons more than would a 738. 32 daily flights each way means 64,000 gallons more fuel each day, and at $3/gal, that equals about $192,000 more for the MD-80s each day over 738s.
While I believed the efficiencies and cost savings were real when the 738s were banished from ORD, these 32 West Coast flights alone cost AA about $70 million more each year in fuel, which probably outweighs any cost savings from isolating the 738s away from ORD.
AA is taking delivery of two new 738s each month during 2009 (23 total); I doubt they will all be assigned to MIA for new routes. My guess is that most of them are immediately placed at ORD for LAX/SFO/SEA/SAN/SJC/PHX flights, but I've been wrong before.
While I believed the efficiencies and cost savings were real when the 738s were banished from ORD, these 32 West Coast flights alone cost AA about $70 million more each year in fuel, which probably outweighs any cost savings from isolating the 738s away from ORD.
AA is taking delivery of two new 738s each month during 2009 (23 total); I doubt they will all be assigned to MIA for new routes. My guess is that most of them are immediately placed at ORD for LAX/SFO/SEA/SAN/SJC/PHX flights, but I've been wrong before.