The DOT Service Animal Air Transportation Form, explained
For air travel in the United States, an airline may require one document: the U.S. Department of Transportation Service Animal Air Transportation Form.

Photo: Egor Gordeev / Unsplash
What the form attests
The form confirms that your dog was individually trained to do work or perform tasks for your disability, and that it is trained to behave safely in public. It is completed and signed by the handler.
How to complete it
Airlines post the form and may ask you to submit it in advance, often 48 hours before departure. The attestation stands on a real fact: the dog was individually trained. A qualified trainer attestation makes that fact easy to support.
In the cabin, at no charge
Under the Air Carrier Access Act and 14 C.F.R. Part 382, an accepted service dog flies in the cabin with you, not as cargo, at no additional charge.