What is Rule 240?
Rule 240, or what the airlines refer to in “contract of carriage”, basically describes the airlines responsibility when a flight is delayed or canceled. It mandates that an airline facing a delayed or canceled flight has to transfer you to another carrier if 1) the second carrier could get you to your destination more quickly than the original line and 2) it has available seats. However it does not cover “force majeure” events such as weather, war, strikes or “acts of God”.
There seems to be some debate that Rule 240 actually still exists. Every airline has a Rule 240 even if it’s called something else in the contract. This article has a quick reference to Rule 240 for several American airlines.
Since contracts are always being updated and not necessarily announced it is advised that you know your airline carrier’s current rules, read your airline contract of carriage, print it out and bring it with you whenever you fly. If you unfortunately do find your flight being delayed or canceled and you want to try using Rule 240 at the ticket counter, present representative with their airline’s own policy and then ask about it in a nice way. Agents are usually much more accommodating dealing with a nice person than the pushy and demanding ones that are numerous and frustratingly annoying when cancellations occur.