Service Animals :

Carriers must permit dog guides or other service animals with appropriate identification to accompany an individual with a disability on a flight. Identification may include cards or other documentation, presence of a harness or markings on a harness, tags, or the credible verbal assurance of the passenger using the animal.

If carriers provide special information to passengers concerning the transportation of animals outside the continental United States, they must provide such information to all passengers with animals on such flights, not simply to passengers with disabilities who are traveling with service animals.

Carriers must permit a service animal to accompany a traveler with a disability to any seat in which the person sits, unless the animal obstructs an aisle or other area that must remain clear in order to facilitate an emergency evacuation, in which case the passenger will be assigned another seat.