Dog travel, answered

One that fits under your airline's seat — roughly an 18 × 11-inch footprint, but with a height limit that ranges from about 8.5 inches (Southwest, JetBlue) to 11 inches (United, Delta). Height is the number that gets carriers rejected. Check your airline in our under-seat dimensions matrix.

For major US airlines, roughly $99–$150 each way as of mid-2026 — per direction and per pet, so a round trip is about double. The fee often costs more than the carrier itself. Always confirm the current fee on your airline's page.

Small dogs that fit — with room to stand and turn — in a carrier that fits under the seat, generally meaning the dog plus carrier is under about 20 pounds on most US airlines. Larger dogs travel in cargo (a stricter, separate process). Snub-nosed breeds face extra airline restrictions.

Soft, for in-cabin travel — it flexes to squash under a tight seat and is lighter through a terminal. Hard carriers are for cargo, which has entirely different rules. Every carrier in our flight roundup is soft-sided for that reason.

For domestic in-cabin travel, many US airlines don't require one, but some do and rules change — check your airline. International travel almost always requires health certification on a strict timeline, so start weeks ahead. Keep vaccination records with you regardless.

An independently certified one. The Center for Pet Safety crash-tests restraints to a published protocol, and the Sleepypod Clickit line is its reference certified harness. See our crash-tested harness roundup for the honest tiers.

Almost none are. The raised boosters sold as "dog car seats" are containment devices, not crash restraints — the tether stops a dog roaming, it isn't validated to hold in an impact. For that, use a crash-tested harness, on its own or clipped into the booster. More in our dog car seat roundup.

Always a harness. A tether clipped to a collar concentrates crash or sudden-stop force on the neck; a harness spreads it across the chest. This is the single most important rule of restraining a dog in a car.

Soft if your dog is calm and crate-trained — lighter, cheaper, packs flat. Hard if your dog chews, digs, or panics — a soft crate is fabric and a determined dog is through it. Full breakdown in soft vs hard dog crate.

Big enough to stand, turn around and lie down, and no bigger. Measure nose to base of tail and floor to top of head sitting, add three to four inches to each. Oversizing isn't kinder — it lets a dog slide around in transit.

For an iPhone household in a populated area, yes — cheap, no subscription, year-long battery. But an AirTag is not GPS: it has no live location and is only found when a nearby iPhone reports it, which fails in empty countryside. For a roaming or rural dog you need real cellular GPS. See our GPS tracker roundup.

Most real-time cellular GPS trackers do, because they use a mobile data connection to report live location — the fee is the ongoing cost, not the device price. A few advertise 'no subscription' but trade reliability for it and may still need a SIM. Read the fine print.

Buy one with a real lock switch, not just a flip cap — that's what holds the trough shut in transit. Every bottle in our water bottle roundup has one; cheap bottles that rely on a flip cap are the ones that leak.

As a rough guide, about an ounce of water per pound of body weight per day, and more in heat or on hard exercise. Offer it regularly rather than waiting for the dog to seem thirsty, and carry a collapsible bowl or a dog water bottle so you can.

Roughly every 2–3 hours to toilet, drink and stretch — more for puppies and seniors. Clip the leash on before opening any door. The full pack list is in our road-trip checklist.

No, and we say so plainly. We don't own a test lab. We compile the published specs, cross-check them against airline limits and independent safety certifications, and do the math — and we cite it. Where we can't verify something, we flag it. Our full method is on how we research.