DEN-ORD 13 miles difference UA vs AA
 

I notice UA awards me 888 miles (plus elite bonus) for a DEN-ORD trip but AA gives me 901 (plus elite bonus). Wat?

I guess the bigger question should be why I care.

I wonder if only one of them adjusted mileage when DIA opened.

At least you aren't being shorted:
http://www.gcmap.com/mapui?P=den-ord

Perhaps it has to do with the amount each has to taxi at DEN and ORD?:D

DIA moved from the Stapleton site to the current site back in the 90's. It looks like UA recalculated the distance after the move and AA did not.

US also calculates mileage from Stapleton. I consistently get shorted between PHX-DEN on US. I guess their PHL/CLT-DEN customers get my missing miles.

Being a semi-frequent CLT-DEN flyer, I thank you. :D

I believe 900 miles is the threshhold for AA to provide a meal in domestic F at meal-times instead of a snack. So all meal-time ORD-DEN flights receive a full meal rather than a snack.

What about the other question, why DO you care? I suppose if you fly it weekly it'll add up but...

every mi counts, but the difference is much too small to change programs for...

Happens all the time with AC. Almost every route is awarded a few miles fewer than other carriers...

Back when Stapleton was open, I was flying often to Seattle, which UA listed as 1,007 miles. This meant I needed 3 of the old upgrade certs to get in first. I kept hoping that DIA would cut it below 1,000, but then I stopped flying To Seattle and never went back to check.

That's UA for you. AA has a 50-mile leeway on these.

There will always be a trip just over any cutoff, of course. Unofficially, when they were paper, they'd usually take three AA stickers for the 1,562-mile BOS-DFW trip. In the electronic system, it's always four.