Anyone who flies American Airlines should read the "Simply Flying" article linked below. Those who typically depend on other US-based airlines should stay alert for similar policy changes from their airlines of choice.
Effective September 30, AA introduced a new policy of not involuntarily bumping anyone; over-sold flights will be held (delayed if necessary) until enough volunteers can be bribed to take a later flight.
Volunteers may (will?) be able to negotiate a guaranteed slot on the next flight, even if it is already fully booked--thus possibly causing cascading issues.
On-site employees will have the freedom to increase the level of the bribes as necessary to accomplish the no-bumping target.
This seems a customer-friendly change, but those on routings involving tight transfers should be aware of this new potential reason for a late departure.
https://simpleflying.com/american-airlines-ends-involuntarily-bumping-passengers-off-flights/
The news originated with "View from the Wing", whose article has more details: https://viewfromthewing.com/exclusive-american-airlines-will-no-longer-bump-passengers-volunteers-can-get-the-next-flight-even-if-its-full/