<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by L-1011:
It's a frequent flyer program, not a frequent payer program, hence same amount of miles for the trip should be given. American gives different amount of points for the same trip depending on the fare paid.</font>
corrected for grammer by tfjim
Not entirely correct. Points are mostly derived from the class-of-service paid for, somewhat unrelated to price. There is a distinction in economy between full and discount fares. Ironically, it used to be that on American one could only reach their very top tier by attaining 100,000 points, which meant 200,000 miles of discount economy flying. Ouch. This has only recently been changed so that one could earn Executive Platinum (highest) by flying 100,000 discount miles.
TWA, before it was consumed by AA, had a dual elite-earning system that I was very much a fan of. One could earn via miles or $$ spent. IIRC, $5,000, $10,000, and $20,000 were the dollar spend thresholds. Did I mention I was a fan of this system?