The number of service dogs on airplanes has drastically risen over the past couple of years. Service dogs and other emotional support animals are allowed to sit with their owner on the plane, causing many issues for airlines.
Some of the dogs are very big, resulting in cramped seating and uncomfortable passengers. Many airlines also reported an increase in biting incidents and complaints of dogs urinating and barking.
Due to these issues, airlines are beginning to crack down on requirements for service dogs to decrease the number of animals on planes. Some airlines have even banned specific breeds from flying.