Airline Pet Temperature Rules: When Flying Is Banned
Every article about airline heat embargoes gives you a neat four-carrier comparison table. Two of those carriers stopped flying household pets in cargo. Here is what the rules actually are in 2026, taken from the airlines themselves, and the forecast check that grounds more pets than the headline number does.
Key takeaways
- The big news is not the temperature rule, it is that cargo pet travel has mostly closed. United suspended its PetSafe program and has not restored it. Delta Cargo has a global embargo on household pet shipments.
- American Airlines Cargo still ships pets, and its window is 45°F to 85°F. It will not fly a warm-blooded animal above 85°F or below 20°F at all.
- Between 20°F and 44°F you need a vet-signed acclimation letter naming an exact temperature, not a general note.
- The forecast is checked at origin, every connection and the destination, at departure and arrival times, and Delta's window extends up to 2 hours after landing domestically.
- Flat-faced breeds are banned outright from cargo by American regardless of the weather, and that list is longer than most owners expect.
Start here, because most articles skip it
Search for airline pet temperature restrictions and you get a tidy comparison table: this airline allows 85 degrees, that one 80, this one needs a letter below 45. It looks like a menu you can shop.
It is not a menu any more. For most American pet owners in 2026, the honest first answer is that your dog either fits under the seat in front of you or it probably is not flying, and the temperature rules only become relevant in the narrow case where cargo is still an option at all.
Straight from the airlines, not from an aggregator:
- United says plainly: "We no longer let you check your pets through the PetSafe program. Pets can only fly in cargo when traveling with certain active-duty military or State Department employees."
- Delta Cargo states it "has implemented a temporary global embargo on household pet shipments," with a limited exception for active US military and Foreign Service Officers on permanent change of station orders.
- American Airlines Cargo still accepts household pets from the general public, subject to the temperature, breed and aircraft rules below.
That is the actual landscape. If you read a 2026 article that compares four carriers' heat embargoes as though you can pick between them, it was written from older articles rather than from the carriers.
The temperature rules that are still live
Where cargo pet travel does still happen, the numbers are strict and they are not negotiable at the counter.
| Carrier | Household pets in cargo? | Accepted temperature range | Cold-weather paperwork |
|---|---|---|---|
| American Airlines Cargo | Yes, general public | 45°F to 85°F. Never above 85°F or below 20°F | Acclimation letter required 20°F to 44°F |
| Delta Cargo | Embargoed, except US military and Foreign Service on PCS orders | 20°F to 80°F for live animal shipments | Certificate of Acclimation required 20°F to 45°F |
| United | No, except certain active-duty military and State Department | Not applicable to general passengers | Not applicable |
| Any carrier, in cabin | Yes, if the pet fits an under-seat carrier | No temperature embargo applies | None |
Note the bottom row, because it is the one that solves most people's problem. In-cabin travel has no temperature embargo. The cabin is climate controlled and your pet never sits on a ramp. Every heat embargo story you have read is a cargo story. If your pet is small enough to travel under the seat, August and January are simply not a weather question.
The rule that actually gets pets bumped
Owners plan around the temperature at the airport they are standing in. That is not how the check works, and this is where trips fall apart at 5am.
American's policy states the restriction applies "to origin, connection and destination cities," based on the actual or forecast temperature "for each flight departure time and flight arrival time for each station on the itinerary." Their own worked example is a dog flying Los Angeles to Rochester via Chicago: you check the LAX forecast for the 6 to 7am drop-off hour, the Chicago forecast for the 1pm to 3pm connection window, and the Rochester forecast for the 5pm arrival hour. Any one of those three exceeding the limit stops the trip.
Delta goes further still. Its temperature guidelines say limits apply "at all times that the animal is on the ground while in Delta's possession," including at an offsite kennel during an overnight or comfort stop, and that recovery of the animal "can be as much as 2 hours (Domestic) and 4 hours (International) after flight arrival." So a 4pm arrival into a city forecast to hit 82°F at 6pm is a problem even though the flight itself landed in an acceptable window.
Two practical consequences fall out of that:
- A connection roughly triples your exposure. Three cities, three forecasts, three chances to fail. Delta has limited live animal shipments to one connection since 2018 for exactly this reason. Book nonstop wherever it is remotely possible.
- Your departure city being fine is worth very little. A cool Seattle morning does not help if Phoenix is 96°F when the plane lands.
Delta's own official source for validating domestic temperatures is weather.gov, so you can run the exact same check yourself days ahead: pull the hourly forecast for every city on the itinerary at the hours your pet will be on the ground. Download WeatherPets and pick your pet to keep that forecast somewhere you will actually look at it.
The acclimation letter, and the detail people get wrong
Between 20°F and 44°F, American will still fly your pet, but only with a letter of acclimation signed and dated by a licensed veterinarian. The mistake is treating this as a formality your vet can scribble.
The letter must state the exact lowest temperature, between 20 and 44 degrees Fahrenheit, that the animal may be exposed to. American's wording is "the animal(s) in this shipment is acclimated to a temperature of [exact temperature]." If the forecast at any station sits below the number your vet wrote, the pet does not fly. Write 40 to be conservative and a 35-degree morning grounds you.
There is a second clause almost nobody reads: American will also decline transport if the maximum time the animal may be exposed to temperatures below 44°F is less than 45 minutes. And if your health certificate already includes an acclimation statement, you do not need a separate letter.
Cold-blooded animals are exempt from these temperature restrictions entirely, packaged per IATA Live Animal Regulations. Delta's exemption list also covers commercial bird shipments, day-old chicks, laboratory mice and rats, hatching eggs and live tropical fish. Rabbits, chinchillas and sugar gliders are not exempt: they carry the same 20°F to 80°F limits a dog does.
Breed bans beat weather rules
If you own a flat-faced dog or cat, the temperature question may never arise, because American will not carry the breed in cargo at any temperature. The stated reason is "the risks associated with their hereditary respiratory issues," and the list is long:
Dogs: Affenpinscher, American Bully, American Staffordshire Terrier, Boston Terrier, Boxer (all breeds), Brussels Griffon, Bulldog (all breeds), Cane Corso, Chow Chow, Dogue de Bordeaux, English Toy Spaniel, Japanese Chin, Lhasa Apso, Mastiff (all breeds), Pekingese, Pit Bull, Presa Canario, Pug (all breeds), Shar Pei, Shih Tzu, Staffordshire Terrier and Tibetan Spaniel.
Cats: Burmese, Exotic Shorthair, Himalayan and Persian.
Mixed breeds must be declared with the predominant breed and the word "mix," so a Frenchie cross is not a loophole. The underlying physiology is the same one that makes these breeds struggle on a warm walk: a shortened airway that cannot move enough air to cool an animal under stress. Our guide to flat-faced breeds and heat risk explains why a cargo hold is one of the worst possible environments for that anatomy.
Do not sedate, whatever you have been told
American will not knowingly accept a sedated or tranquilised dog or cat, and cites the American Veterinary Medical Association's recommendation directly: sedated pets are at higher risk of respiratory and cardiovascular problems at altitude. This is worth repeating because well-meaning advice to "give them something to take the edge off" still circulates widely.
The alternative that actually works is unglamorous and slow: acclimate the pet to the travel crate weeks in advance. Leave it open in the house with a chew and familiar bedding inside so the crate becomes a normal place rather than a thing that appears on the worst morning of their year. The AVMA's travel FAQ covers crate conditioning and pre-trip vet checks in more detail.
How to plan a trip that does not get cancelled
- Measure your pet against an under-seat carrier first. If they fit, the whole embargo question disappears. This is the single biggest fork in the road.
- Book nonstop. Every connection adds another city and another forecast that can ground you.
- Fly the right end of the day. In hot months, take the earliest morning or latest evening departure. In cold months, take a mid-day flight when temperatures are highest. This is the opposite of what most people book.
- Pick the shoulder seasons. April, May, September and October keep nearly every US city inside the 45°F to 85°F band all day. Our city-by-city temperature study shows which cities lose which months.
- Check all three cities the week before, then again the night before. Use the hourly forecast at the hours your pet is on the ground, including the arrival buffer.
- Have a plan B before you need one. Ground transport, a later date, or a shorter drive to a nonstop airport all beat finding out at the cargo counter.
None of this is meant to talk you out of flying with a pet. It is meant to make sure the trip you booked is the trip that happens, because the alternative is a very bad morning with a crated animal and no options.
Airline pet temperature FAQ
What temperature is too hot to fly a dog in cargo?
Above 85°F, American Airlines Cargo will not transport warm-blooded animals at all, and its normal accepted range is 45°F to 85°F. Delta Cargo's live animal limit is 80°F, though Delta currently embargoes household pet shipments except for US military and Foreign Service personnel on transfer orders. The limit applies at the origin, every connection and the destination.
Can my dog still fly in cargo in 2026?
Only on some carriers. United suspended its PetSafe cargo program and now carries pets in cargo only for certain active-duty military and State Department employees. Delta Cargo has a temporary global embargo on household pet shipments with a similar military exception. American Airlines Cargo still accepts household pets from the general public, subject to temperature, breed and aircraft restrictions.
Do temperature embargoes apply to pets in the cabin?
No. Temperature embargoes apply to animals travelling as cargo, because those animals wait on ramps and in holds. A pet small enough to travel in an under-seat carrier in the cabin is not subject to a heat or cold embargo.
What is an acclimation letter and when do I need one?
It is a letter signed and dated by a licensed veterinarian stating the exact lowest temperature, between 20°F and 44°F, that your animal may be exposed to. American requires it whenever forecast ground temperatures at any station fall in that range. If the forecast drops below the number your vet wrote, the pet will not be accepted.
Why are French bulldogs and pugs banned from cargo?
Because of the respiratory risk that comes with a shortened airway. American Airlines Cargo will not accept brachycephalic and snub-nosed dogs and cats, including all bulldog and pug breeds, Boston Terriers, Boxers, Shih Tzus, Pekingese and Chow Chows, plus Persian, Himalayan, Burmese and Exotic Shorthair cats. Mixed breeds must be declared with the predominant breed.
Should I sedate my pet for a flight?
No. American Airlines will not knowingly accept a sedated or tranquilised dog or cat, citing AVMA guidance that sedation raises the risk of respiratory and cardiovascular problems at altitude. Crate conditioning in the weeks before the trip is the recommended alternative. Talk to your vet before giving your pet anything at all before a flight.
Your daily forecast, delivered by your own pet.
A note on health: This article is general information, not a substitute for professional veterinary advice. If you are worried about how your pet will cope with air travel, particularly a flat-faced breed or any serious or emergency health concern, contact your veterinarian right away. Our guidance draws on trusted veterinary sources, including those linked above.
