Dog Carriers for Planes: Airline Size Rules, Fees and How to Choose in 2026

Dog carriers for planes are ventilated, leak-proof pet containers that let a small dog fly in the cabin, stowed fully under the seat in front of you. As of September 2026, Delta Air Lines and American Airlines both recommend a soft-sided carrier of no more than 18 x 11 x 11 inches, and each charges $150 each way on domestic flights. Your dog must be able to stand and turn around inside. Larger dogs fly in the hold or as cargo in a hard crate built to IATA rules.

This guide is published by Animal Passport and was last updated on 29 September 2026. It uses the airlines' own pages, the International Air Transport Association (IATA), the U.S. Centers for Disease Control and Prevention (CDC) and the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS). Airline pet rules change often, so check your airline's page again before you buy.

What is an airline-approved dog carrier?

No government certifies a carrier as "airline approved". Airlines accept any carrier that meets their own written rules. In practice, each airline checks four things:

• Fit under the seat: the carrier must go fully under the seat in front of you. Delta says maximum carrier size depends on the aircraft, because under-seat space differs from plane to plane (Delta Air Lines, 2026).
• Room for the animal: Delta requires that your pet can move around without touching or sticking out of the sides. Southwest requires that the whole dog, head and tail included, fits inside and can stand up and move easily.
• Ventilation and leak-proofing: American Airlines requires soft carriers that are padded, water-repellent and have mesh ventilation on three or more sides (American Airlines, 2026).
• Security: the door must stay closed. Delta requires your pet to stay in the kennel in the gate area, during boarding and in Delta Sky Club lounges.

Airline carrier size limits and fees compared (2026)

The table below lists the in-cabin limits each airline published on its own website when we checked in September 2026. We could not load United's website during our research, so its row uses figures from an independent 2026 review of airline pages and is marked as unverified.

Where the sources disagree

Southwest is the clearest example of carrier sizes being repeated wrongly. Southwest's own Help Center lists a maximum of 18 x 10.5 x 10 inches for carriers other than its own branded one. Several 2026 blogs and retailers still quote 18.5 x 13.5 x 8.5 inches. Those same third-party sites also disagree on Southwest's pet fee, some saying $95 and others $125. If you fly Southwest, trust the airline's page over any shopping guide.

Delta has a similar conflict between its own pages. Delta's consumer page says in-cabin kennels need ventilation on three sides for domestic travel and four sides for international travel. Delta's travel-agent policy page says "at least two sides". If you buy a carrier with mesh on four sides, it meets both versions.

You will also often see a "20 lb pet-plus-carrier limit" quoted as a general rule. American Airlines' own page applies a 20-pound combined limit only to premium cabins on its three-cabin Airbus A321T (American Airlines, 2026). Delta's pages do not publish a general weight limit. What matters is fit and comfort.

How to choose a dog carrier for a plane: 7 steps

1. Confirm your dog can fly in the cabin. IATA notes that only small dogs and cats can travel in the cabin, and some airlines do not allow cabin pets at all (IATA Traveler's Pet Corner, 2026). Also check the route. For example, American does not allow carry-on pets on trans-Atlantic or trans-Pacific trips, and Delta does not allow cabin pets to or from the United Kingdom, Australia or Hawaii.
2. Get the exact limit for every flight segment. American says hard-sided kennels cannot exceed the under-seat space of any aircraft on your journey. That is why a hard carrier that fits a mainline jet can be too big for a regional American Eagle flight.
3. Measure your dog standing. Measure from nose to base of tail, and from the floor to the top of the head or ear tip. Your dog needs enough room to stand and turn around, not only to lie down.
4. Choose soft-sided for the cabin. Delta, American and Southwest all recommend soft-sided carriers because they flex to fit under seats. American warns that the carrier must still fit without being squashed down excessively.
5. Check the build. Look for a leak-proof base, mesh on three or four sides, strong zips or a locking door, and a padded, water-repellent shell.
6. Plan your cabin bags. On American, the pet carrier plus one personal item or one carry-on bag is allowed, not both. Delta's rule is the same.
7. Book your pet's space early. Delta allows up to four pets in its Main and Comfort cabins and two in domestic First, first come, first served. American allows up to five carriers on American Eagle regional jets. IATA advises reconfirming at least 48 hours before departure.

Hard crates for the hold and cargo: IATA Container Requirement 1

If your dog is too big for the cabin, it needs a rigid crate built to IATA Container Requirement 1 (CR1). This is the standard for cats and dogs in the IATA Live Animals Regulations (LAR). The IATA says its LAR is the worldwide standard for moving live animals on commercial airlines, and the current edition took effect on 1 January 2026.

IATA gives this formula for the minimum internal size of a single-dog crate (IATA, 2026):

• Length = A + half of B. A is the length from nose tip to base of tail. B is the height from the ground to the elbow joint.
• Width = C x 2. C is the width across the shoulders or the widest point.
• Height = D + bedding. D is the standing height to the top of the head or ear tip, whichever is higher.
• Snub-nosed breeds need a crate 10% larger.

Airline rules for checked crates build on IATA's. American Airlines requires a door of welded or cast metal and a top and bottom secured with bolts or screws. It also requires food and water dishes fixed inside, ventilation on three sides for domestic trips and four for international, and a total pet-plus-kennel weight of no more than 100 pounds (American Airlines, 2026). Delta requires checked or cargo kennels to follow USDA guidelines, with enough room to stand, sit upright, turn around and lie down naturally.

Access to the hold is now limited. American and Delta both accept checked pets only for active-duty U.S. military and U.S. State Department Foreign Service personnel traveling on official orders. Everyone else ships through American PetEmbark or Delta Cargo. Both airlines also refuse snub-nosed dog breeds as checked pets and set temperature limits. American, for example, will not carry a checked pet if the temperature anywhere on the route is above 85°F or forecast to be.

Preparing your dog for the carrier

IATA advises letting your animal get used to its crate "a few weeks or months" before the flight. It notes that animals travel well when they are already comfortable in their carrier. IATA also suggests cutting food the day before while still giving water, walking your dog before check-in, and giving a light meal about two hours before handing the animal to the airline.

IATA "continues to endorse recommendations not to sedate or tranquilize pets" in transit. If sedation is needed for medical reasons, a veterinarian should direct it and record it on the health certificate. (IATA Traveler's Pet Corner, 2026)

American Airlines goes further and refuses sedated or tranquilized pets. It cites the American Veterinary Medical Association (AVMA) and the higher risk of breathing and heart problems at altitude. Talk to your own veterinarian before your dog is given any medication.

Documents: the carrier is only half the job

A perfect carrier will not get your dog on board without the right documents. The main official schemes are listed below.

Entering the United States: CDC dog import rules

Since 1 August 2024, the CDC has based its rules for dogs entering the U.S. on where the dog was vaccinated and which countries it has been in during the previous six months (CDC, 2024). According to Delta's summary of the rule, every dog entering the U.S. must be at least six months old, be microchipped, look healthy and travel with a CDC Dog Import Form receipt. Dogs that have been in high-risk rabies countries need extra paperwork.

Leaving the United States: USDA APHIS

USDA APHIS advises contacting a USDA-accredited veterinarian as soon as you decide to travel abroad with a pet. The vet can confirm what your destination requires and help you get a USDA-endorsed health certificate (USDA APHIS, page last modified 20 March 2026). For dogs going to Mexico, Delta and American both say a New World Screwworm Inspection Certificate from a USDA-accredited vet is required. It must be issued no more than five days before arrival.

European Union and Great Britain

The European Commission says non-commercial pet movements into and within the EU now fall under Commission Delegated Regulation (EU) 2026/131, which sits under Regulation (EU) 2016/429, the Animal Health Law. For Great Britain, GOV.UK requires dogs to be microchipped before their rabies vaccination. Travel is allowed at least 21 days after vaccination. Most dogs also need tapeworm treatment between 24 hours and 5 days before arrival. Delta requires pets flying to the EU to be at least 15 weeks old.

How Animal Passport differs from a pet travel passport

People searching for travel gear often see the word "passport", so this distinction matters. Animal Passport is not an EU pet passport, an airline pet document or a government-issued travel certificate. It does not replace a microchip, a rabies certificate, a CDC Dog Import Form or a USDA-endorsed health certificate. No airline listed above accepts it as travel paperwork.

Animal Passport is a digital animal and livestock identity record built on muzzle biometrics. An animal's nose print is unique, much like a human fingerprint. Owners capture it with a phone. The record links the owner, breed, estimated age, body condition and vaccination history. Age is estimated from a dental photograph and comes with a confidence score. Body condition is scored from 1 to 5 from a side-profile photo. In August 2025, Animal Passport was used during livestock flood rescue in Pakistan. Paper tags had washed away, and farmers used it to reclaim their animals.

USDA APHIS draws the same line. It says animals such as pigs and chickens do not count as pets for pet-travel purposes and fall under separate import and export rules. Airline carrier rules and pet passports cover companion animals on passenger flights. Biometric livestock identity serves a different purpose: proving who owns an animal on the farm and after disasters. For more on livestock identity, see the Animal Passport blog.

Quick pre-flight checklist

• Check the carrier size limit for every flight on your airline's own page, and measure your carrier with the dog inside.
• Confirm your dog can stand and turn around in the zipped carrier.
• Book the pet with the airline and reconfirm 48 hours before departure.
• Carry the microchip number, rabies certificate and any CDC, USDA or destination forms.
• Put a permanent ID tag and a temporary travel ID tag on the collar, as IATA recommends.
• Allow extra check-in time. Delta checks cabin pets at its Special Service Counter, and you must take your dog out of the carrier at security.