United Airlines: Support animals not allowed on flights longer than 8 hours

United Airlines is changing its policies on emotional support animals on its flights.

Beginning Monday, support animals will not be allowed on flights longer than eight hours.

United says it has seen more on-board animal-related incidents, adding many are not used to spending so much time on a plane.

The airline says it also will not allow kittens or puppies less than four months old as support animals, in-cabin pets or service animals.

Many airlines also require at least 48 hours notice as well as extra documentation.