Special documentation cannot generally be required of a person traveling with a service animal unless the carrier has reason to doubt the animal is a service animal after first speaking with the handler, possibly asking what tasks the animal is trained to perform. However, documentation is required of a person traveling with an Emotional Support Animal in the form of a doctor's letter.
A person traveling with an ESA must have a letter, not more than one year old, on letterhead, from a mental health professional stating all of the following:
1. That the passenger has a mental health-related DISABILITY listed in the DSM IV. Note it is not just a mental illness diagnosis, but a mental illness Airlines are not permitted to require the documentation to specify the type of mental health disability, e.g., panic attacks.
2. That the presence of the animal is NECESSARY to the passenger's health or treatment.
3. That the individual writing the letter is a licensed mental health professional and that the passenger is under his or her care. NOTE: Airlines may also require documentation including the date, type, and state of the mental health professional's license.
"The purpose of this provision is to prevent abuse by passengers that do
not have a medical need for an emotional support animal and to ensure that
passengers who have a legitimate need for emotional support animals are
permitted to travel with their service animals on the aircraft."