Airline pet rules are written around a compact dog, not a long one. A carrier that clears the length limit on one airline can be oversize on the next, and a height rule can stop a dog that fits the floor plan perfectly. This guide sets the published in-cabin carrier size limits for a long-bodied dog side by side, shows how to measure the dog against them, and covers the cases where a legal-looking box still gets turned away at the gate.
Is there one standard airline pet carrier size?
No. Each airline sets its own maximum and the published figures do not agree. American Airlines and Delta both list 18 x 11 x 11 in (46 x 28 x 28 cm) for a soft-sided kennel. Air Canada lists 43 x 40 x 20 cm (17 x 16 x 8 in). SAS lists 40 x 25 x 23 cm with a combined cap of 8 kg including the pet. All four figures were retrieved on 2026-09-08 from the airlines’ own pet pages.
The spread matters most on the axis a long dog cannot fold away. Among these four airlines the shortest published length limit is 40 cm at SAS and the longest is 46 cm at American Airlines and Delta, a 6 cm difference on the dimension that decides whether a long-backed dog lies down flat. A carrier marketed as airline approved can be legal on an American Airlines segment and oversize on a SAS leg of the same trip.
Why do standard in-cabin carriers fail a long-backed dog?
Standard carriers fail a long-backed dog because they are sized by weight while the dog is limited by length and standing height. The American Kennel Club puts the standard Dachshund at usually 16 to 32 pounds and the miniature at 11 pounds and under at 12 months and older. The Royal Kennel Club gives an ideal weight of 4.5 kg (10 lb) and a desired maximum of 5 kg (11 lb). None of those numbers says whether the dog fits inside a 43 cm box.
The breed standards describe the Dachshund by proportion instead of by height. Fédération Cynologique Internationale Standard No. 148 puts body length to height at the withers at about 1.7 to 1.8 : 1, measured from the point of the manubrium of the sternum to the point of the buttock. The Royal Kennel Club writes that “Height at the withers should be half the length of the body, measured from breastbone to the rear of thigh,” implying a ratio closer to 2 : 1. The two standards disagree, so treat the ratio as a range and measure the dog in front of you.
How do you measure a long-bodied dog for an airline carrier?
Measure the dog twice, once along the body and once from the floor, then compare both figures against the carrier interior rather than the published exterior maximum.
- Measure body length from the breastbone to the rear of the thigh, the landmark pair the Royal Kennel Club uses.
- Expect that length to run roughly 1.7 to 2 times shoulder height, per FCI Standard No. 148 and the Royal Kennel Club.
- Measure standing height from the floor to the top of the shoulder.
- Compare against the usable interior, since the airline publishes the largest exterior box the under-seat space accepts.
- Confirm the dog can stand without touching the top and turn with no part extending outside.
- Acclimate the dog to the carrier well before the flight.
That interior gap is a principle, not a number. No airline publishes how much usable length a carrier loses to its walls, padding and zips, so measure the carrier you own rather than trusting the exterior figure. Chest girth is a separate sizing question covered in its own article.
Raise the trip with a veterinarian before booking, especially any question about calming a dog for a flight. The American Veterinary Medical Association states, “Consult your veterinarian before giving your pet any tranquilizers or sedatives,” and warns that these drugs “can increase the risk of heart or respiratory problems and generally are not allowed by airlines.”
What does the carrier height limit mean for a dog that has to stand up?
The height limit is the constraint most owners miss, because it is enforced twice. Air Canada caps in-cabin carrier height at 20 cm (8 in), and the American Eagle hard-sided maximum of 16 x 12 x 8 in is also 8 in tall. Yet each of these airlines still requires the dog to stand upright inside. American Airlines requires a carrier “large enough for your pet to stand, turn, sit and lie down in a natural position (without touching any side or the top of the container).”
Air Canada applies the same double test, requiring that pets “must be small enough to stand, turn around and lie down in their carrier … with no part of them extending outside the carrier.” SAS requires the pet to “stand, turn and lie down comfortably inside the carrier.” A long-bodied dog can clear the length limit and still fail on the 8 in ceiling, and whether yours clears it depends on a standing height you have to measure.
Should a long-spined small dog fly in a soft-sided or hard-sided carrier?
The airline may have already decided. Air Canada has required soft-sided carriers only for in-cabin pets since 2025-06-01, which removes the wider hard-shell option some owners plan around. American Airlines still allows a hard-sided carrier at 19 x 13 x 9 in on mainline aircraft and 16 x 12 x 8 in on American Eagle, so the widest hard-shell footprint sits with the shortest ceiling.
Construction rules sit on top of the dimensions. Delta requires a soft-sided kennel to be leak-proof with ventilation openings on three sides for domestic travel and four for international travel. A carrier that meets the length limit but not the ventilation rule is still refused.
Which airlines will not take a dog in the cabin at all?
Some airlines carry no pets in the cabin on any route. British Airways states, “We don’t carry pets in the cabin on any route,” with assistance dogs the only exception and carried free of charge. That turns a connecting itinerary into a real risk, because one leg can be legal and the next impossible with the same dog and the same carrier.
Fees moved recently too. Delta charges USD or CAD 150 domestic on tickets issued on or after 2025-04-08, against 95 before that date, and 200 international. American Airlines charges USD 150 per kennel. Older posts still quote the pre-2025 numbers.
How do published in-cabin carrier limits compare across airlines?
| Airline | Published in-cabin carrier maximum | Movement rule wording |
|---|---|---|
| American Airlines | Soft 18 x 11 x 11 in; hard 19 x 13 x 9 in; Eagle 16 x 12 x 8 in | Stand, turn, sit, lie down, no contact with top |
| Delta | Soft 18 x 11 x 11 in; vents on 3 sides domestic, 4 international | Able to move around in the kennel |
| Air Canada | Soft-sided only since 2025-06-01: 43 x 40 x 20 cm | Stand, turn, lie down, nothing extending outside |
| SAS | 40 x 25 x 23 cm, 8 kg including the pet | Stand, turn and lie down comfortably |
| British Airways | Not accepted in the cabin on any route | Not applicable |
United Airlines, Alaska Airlines and Lufthansa figures could not be confirmed for this article, so they are left out rather than filled in from a third-party chart.
Can a gate agent refuse a carrier that meets the published dimensions?
Yes, because the final judgement is made by staff at the gate. Global News reported on 2019-04-16 that an owner was denied boarding on an Air Canada flight from Quebec City to Toronto with an 8.5 lb Shih Tzu, a dog the outlet observed could stand and turn inside its approved soft carrier. Air Canada said the dog “was too large for the carrier.” The owner, Kristina Botticchio, told Global News, “I’m afraid now, I don’t know if I would fly again; [it] should be one uniform policy.”
That report is a single dated case and the weight cap quoted in it is historical, so read it as an illustration of gate discretion rather than a current Air Canada rule. A dog sitting at the very edge of a published limit has no margin left for a stricter reading on the day.
Frequently asked questions
Is 18 x 11 x 11 the standard airline carrier size?
No. American Airlines and Delta publish that figure, but Air Canada publishes 43 x 40 x 20 cm and SAS publishes 40 x 25 x 23 cm. There is no single industry standard.
Does staying under the weight limit mean the dog fits?
No. SAS caps combined weight at 8 kg and American Airlines applies a 20 lb cap in the A321T premium cabin, but a long-bodied dog is constrained by geometry rather than mass.
What does not count as an airline approved carrier?
A carrier over that airline’s published dimensions, a hard-sided carrier on Air Canada since 2025-06-01, or a soft kennel without the ventilation openings Delta requires.
What paperwork applies to an international trip?
USDA APHIS advises contacting a USDA-accredited veterinarian as soon as travel is decided. For US-vaccinated dogs returning after time in a high-risk rabies country within the past six months, the CDC rabies certification form must be submitted before the dog leaves the United States.
Sources
- American Airlines, “Traveling with pets”, retrieved 2026-09-08 — https://www.aa.com/i18n/travel-info/special-assistance/pets.jsp
- Delta Air Lines, “Pet Travel Overview”, retrieved 2026-09-08 — https://www.delta.com/us/en/pet-travel/overview
- Air Canada, “Travelling with pets”, retrieved 2026-09-08 — https://www.aircanada.com/ca/en/aco/home/plan/special-assistance/pets.html
- SAS Scandinavian Airlines, “Pet in cabin”, retrieved 2026-09-08 — https://www.flysas.com/en/travel-info/travel-with-pets/cabin
- British Airways, “Travelling with pets”, retrieved 2026-09-08 — https://www.britishairways.com/en-gb/information/travel-assistance/travelling-with-pets
- American Veterinary Medical Association, “Traveling with your animal”, retrieved 2026-09-08 — https://www.avma.org/resources-tools/pet-owners/petcare/traveling-your-animal
- United States Department of Agriculture, Animal and Plant Health Inspection Service, “Pet Travel”, retrieved 2026-09-08 — https://www.aphis.usda.gov/pet-travel
- Fédération Cynologique Internationale, “FCI-Standard No. 148 — Dachshund” — https://www.fci.be/nomenclature/Standards/148g04-en.pdf
- The Royal Kennel Club, “Dachshund (Miniature Long Haired) Breed Standard”, retrieved 2026-09-08 — https://www.royalkennelclub.com/breed-standards/hound/dachshund-miniature-long-haired
- American Kennel Club, “Official Standard of the Dachshund” — https://images.akc.org/pdf/breeds/standards/Official_Standard_Dachshund.pdf
- Global News, “Dog denied boarding on Air Canada flight from Quebec City to Toronto”, 2019-04-16 — https://globalnews.ca/news/5171665/dog-denied-boarding-air-canada-flight-quebec-toronto