United Airlines and Pets in Cabin: Fees, Carrier Sizes, and Documents

As of September 2026, United Airlines and pets in cabin means small cats and dogs may fly with you in the passenger cabin for a $150 each-way pet ticket if space is available, while United’s PetSafe cargo program is closed to the general public. United Airlines is a major U.S. carrier that accepts only cats and dogs as in-cabin pets in a hard- or soft-sided carrier that fits under the seat. This guide summarizes United’s published cabin rules, carrier sizes, route limits, and the separate U.S. government documents you may need for international dog travel—distinct from biometric livestock ID tools such as Animal Passport.

Last updated September 2026. Byline: Animal Passport editorial. Always re-check united.com and destination rules before you fly; airline and government requirements can change.

What United allows for pets in the cabin

United Airlines states on its Traveling with pets page that it no longer lets customers check pets through the PetSafe program. Pets can fly in cargo only when traveling with certain active-duty military or State Department employees. For everyone else, the animal must be a cat or dog and stay in the cabin with you if space is available. Pet tickets cost $150 each way, according to United Airlines in 2026.

On most flights, you can bring up to two pets per person, but you must buy two adjacent seats so you can care for both animals. United lists aircraft that allow only one pet per person because under-seat space is limited: Airbus A319, A320, and A321neo; Boeing 737-800 and 737-8 (MAX 8); and Boeing 737-900 and 737-9 (MAX 9).

United publishes no weight or breed limits for in-cabin pets. Fit is the controlling rule: the pet must travel in a ventilated hard- or soft-sided carrier that fits under the seat in front of you. The only animals United allows in the cabin without a carrier are trained service animals under United’s separate service-animal policy. Therapy and emotional support cats and dogs must fly as pets and follow the in-cabin pet rules, United states.

Carrier size requirements

United Airlines lists these maximum carrier sizes on its Traveling with pets page (verified via the September 2026 archived page):

• Hard-sided: 9 in × 17.5 in × 12 in (22 cm × 44 cm × 30 cm)
• Soft-sided: 11 in × 18 in × 11 in (27 cm × 45 cm × 27 cm)

On Boeing 737 MAX flights, United states the pet carrier can be no more than 10 inches tall. The carrier must be ventilated and fit under the seat, or you cannot fly with your pet. Once onboard, the pet must stay in the closed carrier under your seat at all times.

The International Air Transport Association (IATA) Live Animals Regulations Container Requirement 1 (Edition 52, January 2026) sets industry standards for dog and cat containers. For cabin carriage, IATA allows non-rigid construction and does not require spacers or food/water containers inside the cabin carrier, but the animal must still be able to stand, sit erect, lie naturally, and turn about normally while standing. United’s under-seat dimensions are airline-specific and may be stricter than generic IATA sizing formulas—use United’s published maxima.

How to book a United in-cabin pet ticket

1. Book on united.com and select “Travel with a pet” as a traveler, or open My Trips and add a pet to an existing reservation. United states you cannot add a pet in the United app.
2. Pay the $150 each-way pet ticket. Cabin pet space is limited and first-come, first-served.
3. For international travel on United, call to add the pet to your reservation, United advises.
4. If you are bringing two pets, purchase the required adjacent second seat and register both pets.
5. At the airport for domestic flights, check in at a kiosk; United says a special tag for the pet carrier prints there.

You cannot sit with a pet in an emergency exit row, a United Premium Plus seat, or the front row of each cabin. Seat and total-pet limits vary by aircraft. United’s cabin pet-max table includes examples such as up to six pets in Economy on Boeing 767, 777, and 787 aircraft, and lower Economy caps on many narrow-body and regional jets. On Boeing 757-200 Economy, United requires a window seat for the carrier to fit; on certain 737-800/MAX 8 and 737-900/MAX 9 Economy flights, aisle or window seating is required.

Where pets cannot fly on United

United does not allow in-cabin pets to, from, or through a published list of states and countries, including Australia, Hawaii, the United Kingdom, Ireland, New Zealand, South Africa, Brazil, Hong Kong, Thailand, the United Arab Emirates (Dubai), and many others listed on the airline’s Traveling with pets page. Limited footnotes apply (for example, some Guam, Spain/Bilbao, and Taiwan route exceptions). If you connect on partner airlines, check each carrier’s pet policy separately.

Age, health papers, and international rules

United’s age rules, as published in 2026: puppies and kittens must be at least 2 months old on domestic flights; on international flights, dogs must be at least 6 months old to comply with U.S. Centers for Disease Control and Prevention (CDC) requirements, and kittens must be 4 months old to comply with vaccination requirements.

For travel within the United States, United encourages—but does not strictly require—a veterinary certificate of health that includes owner contact details, pet description (breed, sex, age, color, markings), and recent vaccines. For all international flights, including Canada and Mexico, United requires dogs and cats to have a health and vaccination certificate. United also states rabies vaccinations must be completed at least 28 days before travel for dogs and cats departing the United States to international destinations.

Destination countries set their own entry rules. The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) advises contacting a USDA-accredited veterinarian as soon as you decide to travel abroad so the veterinarian can identify required vaccinations, tests, treatments, and any USDA-endorsed health certificate. APHIS notes that country requirements can change at any time and must be verified for each trip. Original endorsed paperwork must accompany the pet; electronic copies are not accepted by destination officials, according to APHIS’s Pet Travel Process Overview (last modified June 18, 2026).

United also flags New World screwworm documentation issues for some Mexico and USDA-related itineraries. Customers traveling with dogs into Mexico must present a New World Screwworm (NWS) Inspection certificate for both service dogs and in-cabin pets, with conditions including a USDA-accredited veterinarian signature issued no more than five days before travel, United states. Dogs originally from Mexico follow different paperwork rules on United’s page—confirm with USDA and Mexican authorities before departure.

Returning to the United States with a dog

If you fly into the United States with a dog, CDC rules apply separately from United’s cabin fee. As of CDC’s Frequently Asked Questions on Dog Importations (updated August 27, 2026), all dogs entering or returning to the U.S. need a CDC Dog Import Form receipt. Dogs that have been only in dog rabies-free or low-risk countries for the past six months still need that receipt and must appear healthy, be microchipped, and be at least 6 months old. Dogs that visited high-risk countries need additional USDA-endorsed or foreign-government rabies documentation, and foreign-vaccinated dogs from high-risk countries may need a CDC-registered animal care facility reservation. Check current CDC country lists before you leave.

Comparison: United cabin pet vs. official export papers vs. Animal Passport

Animal Passport is a digital animal and livestock identity product that captures a muzzle biometric (a nose print unique like a fingerprint), estimates age from a dental photograph with a confidence score, and scores body condition 1–5 from a side-profile photo. In August 2025 it was used in livestock flood rescue in Pakistan so farmers could reclaim animals when paper tags washed away. It does not replace United’s pet ticket, USDA APHIS certificates, or CDC import forms, and it is not a government-issued travel document. For more field notes and identity context, see the Animal Passport blog.

Practical packing and airport tips from United

United recommends packing a collapsible water bowl, leash, treats, and plastic bags for airport time, plus a familiar toy, blanket, or pillow to help keep the animal calm. Pet strollers must be checked in the lobby and count toward checked-bag allowance. Many airports have pet relief areas; United points travelers to airport maps in the United app.

“Once you’re on your flight, there’s only one rule you need to follow. Your pet must stay in their carrier with the door closed, and under your seat at all times.” — United Airlines, Traveling with pets (2026)

Military and State Department exceptions

United publishes pet exemptions for members of the U.S. military on permanent change of station and their spouses, and for State Department foreign service officers and their spouses. Those programs are separate from the standard $150 in-cabin public option and are the pathway for limited cargo movement of pets. Eligible travelers should follow United’s military/State Department pet instructions, not the general PetSafe narrative still found on older third-party sites.

This article is informational reporting for Animal Passport readers in the Airlines & Flying With Pets cluster. It is not veterinary diagnosis or legal advice. Confirm fees, aircraft, and documents on primary United, USDA APHIS, and CDC pages for your exact itinerary.