Currenly, the presence of and enforcement of rule 240 is diminishing. American Airlines, for example, spells out their contract of carriage on their web site. However the contract itself contains no mention of rule 240.
Since rule 240 is no longer federally required, airlines have modified their versions for inclusion in contracts of carriage or elsewhere. American’s rule 240 does appear on their web site outside the contract of carriage and states that a passenger must be who is experiencing a “schedule irregularity":
1. On next AA flight in the same inventory as ticketed if available. If not available, rebook the lowest available inventory in the same cabin as ticketed.
Note: Next AA flight may be either earlier or later than the originally scheduled flight.
Contrary to popular belief, there is no requirement that passengers be reaccomodated on another airline. Passengers are simply to be accomodated on the next available flight. American leaves itself a lot of wiggle room.
According to airfarewatchdog.com, Jetblue, has no traditional rule 240 but will purchase tickets on another airline and give a partial refund in the event of a severe delay. This is, of course, at the airline’s discretion.
Northwest’s 143 page contract of carriage, perhaps, has the most generous rule 240 style offerings for passengers. Northwest’s contract states that they will put you on another airline– in first class if necessary– at their expense if you are delayed 60 minutes or more.
Since rule 240 is airline policy, and not federal regulation, the airlines can change the policies almost at will. There has been a trend toward offering less accommodation to passengers who get stranded due to non-weather events. US Airway’s rule 240 has disappeared all together from its contracts and web sites, leaving passengers unsure of their rights. “Without a contract, the passenger’s rights are pretty much at the discretion of the agent, who, if they want to keep their job, will work within the rules set by management," said a US Airways employee who requested not to be named for this report.