Delta Air Lines says for safety reasons it will require owners to provide more information before their animal can fly in the passenger cabin, including an assurance that it's trained to behave itself.
The airline says complaints about animals biting or peeing and pooping have nearly doubled since 2016.
Starting March 1, Delta will require owners to show proof of their animal's health or vaccinations at least 48 hours before a flight.
\Owners of psychiatric service animals and so-called emotional-support animals will need to sign a statement vouching that their animal can behave. But owners will be on the honor system - they won't have to show, for example, that their dog graduated from obedience school.