How to Fly With a Dog: The Complete Guide

By Jessica Ennis, DVM, CVA

Travel · July 11, 2026 · 4 min read

Flying with a dog is mostly a planning problem, and the dogs that travel best belong to owners who started weeks out, not the night before.

Start with one decision, because it shapes every other choice: where your dog rides. Dogs small enough to fit inside a carrier that slides under the seat in front of you can travel in the cabin on most U.S. airlines. Everyone else flies below deck, either as checked baggage on your own flight or as air cargo booked as a separate shipment. The cabin is the calmer, lower-risk option nearly every time, so if your dog is anywhere near the size cutoff, measure before you assume the hold is the only door open to you.

Then book the trip around the dog. Pick a nonstop route so there are no connections, no crate transfers, and no long tarmac waits. Fly early or late in summer and midday in winter, when ramp temperatures are gentler. Reserve the pet spot the moment you buy your own ticket, because airlines limit how many animals ride per cabin and per hold, and those slots go fast.

Cabin, checked baggage, or cargo, and which fits your dog?

For a cabin dog, the rule that matters is the carrier, not the scale. It has to fit fully under the seat and let the dog stand up and turn around, and your pet stays inside it for the whole flight. Some airlines publish a combined weight limit; American, for instance, caps the dog-plus-carrier at 20 pounds, while others dropped weight caps and enforce only the under-seat dimensions. Soft-sided carriers are usually the smart pick, since they give a little against the seat frame.

Checked baggage and cargo both put the dog in the pressurized, temperature-controlled hold, but they are booked differently and priced differently. Cargo is the route for large dogs, unaccompanied dogs, and most international moves, and it usually runs through a pet-shipping desk rather than the passenger counter. Whichever you use, ask the airline two blunt questions up front: what is the temperature policy, and is my dog’s breed accepted at all?

That second question matters most for flat-faced dogs. Short-nosed breeds, including pugs, French bulldogs, boston terriers, English bulldogs, and shih tzus, overheat and struggle to breathe under stress, and the American Veterinary Medical Association warns they face a disproportionate share of in-flight deaths. Major carriers such as American and United will not accept these breeds in the hold at all. A small snub-nosed dog can still fly in the cabin. A large one may simply have no safe way to fly.

Which documents do you actually need?

For domestic flights, the paperwork is set by your destination, not by a single federal rule. The USDA’s APHIS does not regulate pets moving state to state, the receiving state does, yet most airlines still require a health certificate, a Certificate of Veterinary Inspection issued by your vet within a set window, often ten days of travel. Confirm the exact window with your airline and check your destination state’s rules.

International and re-entry travel is stricter, and one rule catches many U.S. owners off guard. Since August 1, 2024, every dog entering or returning to the United States, including American dogs coming home from a trip abroad, must have a CDC Dog Import Form receipt, be at least six months old, and carry a microchip a universal scanner can read. Dogs that have only been in rabies-free or low-risk countries need only that form; dogs arriving from high-risk-rabies countries face added vaccination and documentation steps. Destination countries layer on their own rules, and some require vaccinations or titer tests months ahead, so research the endpoint early.

How should you choose and prepare the crate?

For a hold-bound dog, buy an airline-compliant hard crate, and buy it early. Under IATA’s standards the crate has to be rigid plastic, metal, or plywood, ventilated on at least three sides for domestic flights and four for international ones, and roomy enough for the dog to stand without touching the top, turn around, and lie down naturally. It needs a water dish that can be filled from outside without opening the door. Snub-nosed breeds should size up, since IATA suggests roughly ten percent larger than the measured formula gives.

Then let the dog live with the crate for weeks. Leave it open at home, feed meals inside it, add a familiar blanket or an unwashed shirt that smells like you, and build up to longer closed stretches. A dog that already treats the crate as a den travels far better than one meeting it for the first time at a loud airport.

Is it safe to sedate a dog for a flight?

Almost never, and never without your veterinarian’s sign-off. The AVMA advises against sedatives and tranquilizers for air travel because they can raise the risk of heart and breathing problems, and those risks climb at altitude, where a groggy dog cannot brace itself in a moving crate. Over-sedation is among the leading causes of animal death in transport, and most airlines will refuse a dog that appears sedated. If your dog’s travel anxiety seems unmanageable, ask your vet about crate acclimation, or about whether this dog should fly at all, rather than about a pill to push it through.

What happens at security and the gate?

At the TSA checkpoint, take the dog out of the carrier and send the empty carrier through the X-ray belt; the dog is never X-rayed. Keep the dog leashed, carry or walk it through the metal detector with you, then expect an officer to swab your hands for explosive residue. Return the dog to the carrier only once you are clear of the lanes. Just before you get in line, walk your dog, offer a little water, and skip a heavy meal so the flight starts on a settled stomach.