Many people are disgusted with the airlines constantly finding new ways to ding passengers, particularly with fees for services that used to be part of the ticket price.
Now American Airlines and possibly others are putting a premium on some conventional aisle seating in coach.
Here is a seating chart for a 30-row airplane:
Note the string of purple aisle seats that extends back as far as row 22. Checking the legend and what the double asterisks mean solves the mystery.
The purple seats are considered “preferred seats” and only go in advance to upper level people in AA’s frequent flier program and those paying full coach fare. The saving grace at American is that they don’t charge a fee for a premium coach seat, unlike some other airlines.
The effect of American’s seating policy is that anyone making a conventional reservation on a discounted ticket even over six weeks before the flight is seemingly only offered a middle or window seat, and a tiny subset of the coach aisle seats — at least on this particular flight. (And despite American’s representation that additional seats will be made available within 24 hours of departure for the peasants in coach, the airline held those seats for assignment only at the airport.)