Health certificate for a US domestic flight
Most guides repeat that a health certificate is mandatory for any US domestic flight. That's false federally, false in eleven states, and yet sometimes true because of the airline. Three separate regimes that get confused constantly.
Washington doesn't regulate your trip
APHIS, the federal veterinary agency, does not regulate the interstate movement of a pet by its own owner. Its authority covers businesses that take custody of an animal for hire — shippers, professional transporters — under the Animal Welfare Act.
In other words, there is no single national rule for a domestic flight with your dog or cat. Each destination state sets its own, and that's where the question actually lives.
Eleven states explicitly exempt personal travel
Most states require a Certificate of Veterinary Inspection — a CVI — for a dog or cat to enter. But eleven of them explicitly distinguish personal travel from sale, adoption or exhibition, and exempt the first:
- California, Texas, Florida, Georgia, Pennsylvania, North Carolina
- Maine, Vermont, Mississippi, South Dakota, Virginia
Why that nuance disappears everywhere else
"A CVI is always required" is easier to write than a fifty-entry map, and it has the advantage of never exposing whoever publishes it. It has a cost for the reader: an unnecessary vet visit, an appointment booked in a rush, sometimes a flight pushed back for a document the arrival state never asked for.
The reverse is more dangerous still. An owner who reads "no certificate needed in the US" and flies into a state that requires one turns up at the counter without it, and finds out at check-in. The right question is never "do I need a certificate in the US", it's "what does the state I'm landing in require".
When a CVI is required, the window matters as much as the document
A CVI isn't permanent. Each state sets its own validity period, usually counted in days before entry — thirty days in Alaska, for instance. A certificate signed too early is as unusable as no certificate at all.
Rabies vaccination follows separate logic, with its own state-by-state requirement window. And some states have quirks nothing would let you guess: Alabama, for example, has refused the federal APHIS 7001 form since 2019 and requires its own document instead.
The airline is a regime of its own
Even when the destination state requires nothing, the carrier can require a health certificate, proof of vaccination, or a form specific to it. That requirement is contractual, not regulatory: it sits in its conditions of carriage, it varies between carriers, and it's enforceable at the counter exactly like a state rule.
This is the costliest confusion in the whole subject. An owner who checked the arrival state's rules and concluded nothing was needed can still be denied boarding by an airline whose own policy asked for a document. The two checks are independent and both have to be done.
The routes that fall outside the ordinary regime
Hawaii is a category of its own: legal quarantine on arrival, a rabies blood titer, paperwork filed ten days ahead. The territories each follow their own logic — Puerto Rico accepts the APHIS 7001 form with no import permit, the US Virgin Islands require the vet's accreditation number on the document, and Guam applies a regime stricter still than Hawaii's.
For those destinations the question is no longer "do I need a certificate" but "how many months do I need to plan for". Treating them as an ordinary domestic flight is the most common planning error on these routes.