Originally Posted by LBJ

I would say in order for this trick to have a decent chance of working you would have to start at least a month out. Once you start hitting the 3, 2, and 1 week marks you will start running into the advance purchase requirements of the lower fare classes. So even if they happen to release some seats in the X bucket, if it has a 3 week advance purchase requirement and you are within 3 weeks of your flight, you will not be able to re-purchase in that class. Also, realize that many lower fare classes often have a 3 night min or Sat night stay requirement. Again, it won't matter if the lower buckets are available if your trip does not meet the fare rules for those classes. The best you can hope for in such cases is a drop in the fare for your existing fare class which is pretty rare.

I read over the DOT rulings, FAQ's, and clarifications and couldn't really find anything that addresses this type of activity. As mentioned above, I don't really think this is what DOT had in mind when they enacted the rule. I suspect that if airlines see significant amounts of this activity, they could request clarification from DOT. I wouldn't assume that DOT would rule in favor of protecting such activity. The other option would be for DL to simply drop the 24-hour worry-free cancellation policy and go with a 24-hour hold policy instead. The DOT rules say either option is acceptable and that the airlines do not have to offer both. I believe this is AA's current policy. Personally, I rather like the current 24-hour cancellation policy, so I'd prefer that people not abuse it.