If you are involuntarily bumped that is one thing, there are clear rules. Sometimes there will be a mechanical issue and a flight gets cancelled so the airline has to route passengers through many different connecting airports to get everyone to their destination. That is when a flight becomes overbooked, if you volunteer to give up your seat and your flight delay is less than 4 hours Delta gives you meal vouchers and $400, $600 if it is over four hours. I don’t volunteer my international flights so I don’t know their policy.

I usually book a free travel day heading home, just in case this happens. Then I have vouchers for me! In the past I have taken trips to Hawaii, first class, just on vouchers! How is that for a little inconvenience?

Hope this info helps!