Flying With a Pet in the Cabin

Published airline policy, read 1 November 2026, each figure linked at the bottom. Policies change and a gate agent has the final say. United and Alaska are discussed below but not tabled — their policy pages would not render for us, and we do not publish figures we have not read.

What each airline publishes

Two things in that table are worth more than the rest. The first is that two of the five do not publish a fee on the policy page at all — American tells you to pay at the ticket counter and JetBlue names only the price of the carrier it sells you. The second is that Delta publishes no maximum carrier size, which sounds generous and is the opposite.

The box that clears everything

This is the arithmetic the category needs and nobody does. Take every published maximum and keep the smallest figure on each axis:

16 × 10.5 × 8 in. That is the carrier that never needs a conversation at a gate, and it is smaller than almost everything sold with the words “airline approved” printed on it — a phrase which, as the carrier ranking explains, is printed by the people selling the bag rather than by any airline.

Why “no published maximum” is the worst answer

Delta publishes that in-cabin kennel dimensions are determined by the aircraft, because under-seat space varies by type, and it recommends a soft kennel of 18 × 11 × 11 in as fitting most aircraft. That is honest about the physics and useless at the point of purchase.

A published maximum is a promise you can measure a bag against before you spend money. A recommendation is a thing an agent can decline. If you are flying Delta and buying once, the defensible move is to buy to the computed box above rather than to Delta’s recommendation, because 18 × 11 × 11 in is over JetBlue’s published height by 2.5 in and over Southwest’s published width by 0.5 in — and almost nobody flies one airline for life.

What the carrier costs you besides the fee

The fee is the visible cost. The allowance is the one people get caught by, and the carriers split three ways:

• American and Southwest — it takes one of your two items. American publishes that with a pet you may bring one additional item: a personal item or a carry-on, not both. Southwest publishes that the carrier “counts as either a personal item or a carryon item”. Either way the pet is occupying a slot you would otherwise pack into.
• Delta — it costs you nothing in allowance. Delta publishes that in addition to the kennel you may bring one personal item or one carry-on. The pet rides free of the baggage arithmetic, which is a materially better deal than the fee alone suggests.
• JetBlue — the page says both. One passage reads “the pet and carrier will count as your carry-on item”; another on the same page reads “your pet and approved pet carrier count as one personal item”. We are not going to resolve that for you by guessing which the airline meant, the same way we do not resolve it when a product listing contradicts itself. Assume the worse reading and you cannot be surprised.

If the carrier is taking your cabin bag slot, the bag that survives it is a personal item you can stuff under the other seat, not a roller. The published personal-item box, carrier by carrier.

The weight limit almost nobody publishes

One airline in the five publishes a number, and it is strict. American publishes a 20 lb maximum for pet and carrier combined, and publishes that it weighs them at check-in. Nobody else in this group publishes a weight at all.

Run that against the carriers themselves. The Sherpa publishes 3 lb empty and the Sleepypod 4.5 lb, so American’s cap leaves roughly 15.5–17 lb of animal. That is a comfortable cat and an uncomfortable question for a mid-sized dog, and it is the figure to check before you book rather than at a scale you did not expect.

The rules that are not about size

• Eight weeks is the floor. American, Delta and Southwest all publish a minimum age of 8 weeks for domestic travel.
• Cats and dogs, mostly. Delta also publishes household birds on domestic flights. JetBlue publishes small dogs and cats only and states plainly that no large dogs are accommodated.
• Breed restrictions are published, and they are about breathing. American publishes named restrictions covering snub-nosed cats — Persian, Himalayan, Exotic Shorthair among them — and a named dog list. Check your breed against the airline’s own list, not against a summary.
• Cabin class can exclude a pet outright. Delta publishes a per-cabin table in which Delta One and Delta Premium Select allow zero pets, First allows two and Main allows four. A paid upgrade can therefore disqualify the animal.
• There is a cap per flight. American publishes a maximum of 20 pet carriers across all cabins. Pets are booked, not just paid for, so the limit is first-come.
• Domestic health certificates are mostly not published as required. None of the five publishes one as a blanket domestic requirement, but JetBlue publishes that vaccination requirements vary by state and that Puerto Rico and the US Virgin Islands require documentation. Hawaii is its own regime entirely.

Two airlines we could not read

United and Alaska are missing from the table on purpose. Both publish pet policy pages; neither would render readable text for us on 1 November 2026, and this site does not print a figure it has not read. Their policy pages are linked in the sources below — go to them directly rather than trusting a summary, which is the right advice for every airline on this page.

It is worth saying why that matters more here than elsewhere. Baggage dimensions get republished accurately because thousands of people check them. Pet rules are repeated carelessly across the web: while researching this page, third-party sources disagreed on Southwest’s fee by $30 and gave three different carrier sizes. The figure in our table, $125, is the one on Southwest’s own published charges page. That is the standard to hold any pet-policy page to, including this one.