A couple of corrections for folks reading of your experiences.
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">During the year, due to delays and/or cancellations on the part of American, I was put on other airlines to reach my destination (I made sure it was Delta). AAdvantage policy is that I do not received AA credit for those flights since it was not flown on American or an American partner. To the best of my knowledge, American is the only airline with that type of policy when I am forced to fly an alternate airline due to the fault of the principle (sic) airline.
In particular, I don't like the way one has to qualify for top tier, American does not allow for segments to get to top tier (Platinum Executive). One has to earn the privilege on points. The base 500 miles on every flight translates into 500 points. However, if one is flying on a discounted coach fare, one gets 0.5 points per mile after the first 500. One gets 1 point per mile in full fare coach and so on. Since I pay for most of my travel out of my pocket, I have no incentive to fly long flights on American. It would take me (on average) about 140,000 base miles (as calculated as 1 flown mile per base mile) to reach the 100,000 points I would need to get Premier Executive status. To get that, I would probably need to fly almost 150 segments (based on my typical flying pattern). And the benefits for Executive Platinum aren't all that much better than regular Platinum.
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AAdvantage has always in my experience given me manual credit for flights purchased but not flown due to involuntary rerouting onto another carrier. One of the great benefits of FT sharing has been learning that this is common practice among airlines.
Regarding having to fly 140,000 miles, that appears to specific to your case apparently relying mostly on shorthaul and low fares. As you probably know you can also earn Executive Platinum on AA through just flying 100K flight miles.