If the animal is an emotional support animal (ESA), then you must tell the airline representative that the dog is an ESA. You will be required to produce a formal letter of prescription for a service dog or ESA from a
licensed mental health professional. A letter from your medical doctor will
NOT be accepted, as the letter must be written by a licensed mental health professional (psychiatrist, psychologist, therapist, counselor, social worker). There is no way around this. In addition, it is becoming increasingly common for airlines to require you to submit a copy of this letter several days prior to the flight.
Click here to find out more about a letter of prescription. Some airlines (Midwest and Frontier, for example) actually require you to have your therapist or licensed mental health professional complete one of their third party verification forms. If you don't have a therapist