Originally Posted by
guv1976
Members of AA's AAdvantage program earn AAdvantage miles based on distance flown on partner airlines -- other than JetBlue. But it's not necessarily a 1:1 earnings situation. You'll earn a percentage of the flown mileage, depending on the fare basis, whether you're flying in a premium cabin, and whether you have elite status in AAdvantage. That percentage might be more or less than 100%, based upon those factors.
Flights on AA and JetBlue will earn miles based on base fare and a multiplier depending on your elite status, if any.
Delta and United do exactly the same thing for partner flying. I've earned 40K+ miles Delta Skymiles on Virgin Atlantic trips which would have only earned 9 to 10K miles if flown on DL based on the fare prices I paid. Unpublished fares (such as fares that are part of certain vacation packages) also still earn based on mileage flown.
Many of us still fly mileage runs primarily to earn points towards status, rather than primarily for redeemable miles. My Virgin Atlantic trips were primarily mileage runs to help me earn Diamond Status on Delta (and not primarily about the redeemable miles). My trips cost $1100 - $1200 and wouldn't have really been worth it for just the redeemable miles alone.