American prints one soft-sided carrier size for every flight it sells, from its biggest wide-body jets to the smallest regional jets on its American Eagle routes: 18 x 11 x 11 inches.
One number sounds simple. What it hides is that the plane still decides how many pets can board, which seats you can take and how much room the seat in front leaves for your carrier.
What to buy: Any soft carrier no bigger than 18 x 11 x 11 inches with mesh on at least three sides, plus a $150 pet fee each way. If you often fly American Eagle, pick one with an inch or two to spare, like the Petsfit Small below.
The four carriers here are measured against that limit, from the roomiest margin to none at all.
The four picks
![[FREE DOWNLOAD] Camping with Your Dog Checklist](https://thenomadpaws.com/wp-content/uploads/2024/06/Camping-with-Your-Dog-Checklist-300x169.jpg)
What American says about carriers
American’s pet travel page recommends a soft-sided carrier and lets it run slightly larger than the under-seat space, as long as it slides under the seat without being squashed hard.
- Soft-sided: 18 x 11 x 11 inches (46 x 28 x 28 cm) at most, whatever the aircraft.
- Hard-sided: up to 19 x 13 x 9 inches on mainline jets, and 16 x 12 x 8 inches on American Eagle.
- Mesh: the carrier has to be padded, water-repellent and ventilated with nylon mesh on three or more sides.
- Fee: $150 per carrier each way, nonrefundable, paid at the airport by card.
- One carrier per person, plus either a personal item or a carry-on bag, not both.
- Weight: no general limit, except on the A321T, where pet and carrier together must stay under 20 lb.
Your pet has to fit comfortably inside the closed carrier and stay there, under the seat in front, for the whole flight.
Why American Eagle changes the answer
The soft-sided limit doesn’t shrink on a regional jet, so a carrier that fits on a mainline Airbus fits the rule on an Embraer too. What shrinks is everything around it.
Mainline jets take up to 20 carriers across all cabins. American Eagle’s CRJ and ERJ jets take five in the main cabin and one in premium, so a busy holiday flight can fill up long before the plane does.
The hard-sided limit also drops to 16 x 12 x 8 inches on Eagle, which hints at how much less room there is under those seats. American doesn’t publish under-seat measurements by aircraft, so on a regional route a carrier with inches to spare is the safer buy.
Four carriers measured against 18 x 11 x 11
Every size and pet-weight figure in this section is what the seller lists on Amazon, so treat them as claims; prices and stock are from 3 November 2026. Measure yours when it arrives, because a quarter inch matters at the gate.
| Spare room (L / W / H) | Mesh | Heaviest pet | Amazon price | |
|---|---|---|---|---|
| Petsfit Small | 2 in / 1 in / 2 in | Top and two sides | 9 lb | $45.11 |
| Petsfit Medium | 1 in / 0 in / 0 in | Top and two sides | 13 lb | $51.28 |
| Sherpa Medium | 1 in / 0 in / 0.5 in | Not stated | 16 lb | $64.99 |
| Lekereise | 0 in / 0 in / 0 in | Five sides | 15 lb | $21.99 |
Petsfit Small Double Expandable Carrier
Most room to spare
Best for: a cat, kitten or toy dog up to 9 lb, and anyone flying American Eagle.
Two inches inside American’s limit on length and height, which is the margin you want under a regional-jet seat.
Outside 16 x 10 x 9 in · pets to 9 lb · bag about 2.6 lb · $45.11 on 3 November 2026
Full details
Petsfit’s Amazon page puts this one at 16 x 10 x 9 inches for a pet of 9 lb or less, and adds a note that it runs on the small side, so measure your pet’s length before you trust the weight figure. It quotes about 2.64 lb for the bag in one line and 2.43 lb in another.
Both side panels unzip, taking it to 23.5 x 16 inches at the gate or the hotel. Petsfit’s page for this two-extension model names American among the airlines its S and M sizes suit, which is a brand claim rather than American’s approval.
Seller on 3 November 2026: Petsfit. Mesh: top and two sides. The dimensions and pet limit are the listing’s word, not a measurement.
Petsfit Medium Expandable Carrier
The brand names American
Best for: cats and small dogs to 13 lb flying mainline.
Inside American’s limit with an inch spare in length, and level with it on width and height.
Outside 17 x 11 x 11 in · pets to 13 lb · bag 2.5 lb · $51.28 on 3 November 2026
Full details
Petsfit’s size guide for this one-side model lists the M at 17 x 11 x 11 inches, 2.5 lb and pets up to 13 lb, and says the S and M sizes are approved for Delta, United and American. That’s the brand speaking, not the airline.
The Amazon title talks about Delta instead and doesn’t mention American. One side panel opens it to 20 x 17 inches for a layover, and it has to be zipped back before you board.
Seller on 3 November 2026: Petsfit. Mesh: top and two sides. The dimensions and pet limit are the listing’s word, not a measurement.
Sherpa Original Deluxe, Medium
Spring frame that gives
Best for: a dog up to 16 lb that’s long rather than tall, in a classic tote.
Inside American’s limit by an inch in length and half an inch in height.
Outside 17 x 11 x 10.5 in · pets to 16 lb · bag 3 lb · $64.99 on 3 November 2026
Full details
On Sherpa’s size table, the Medium is 17 x 11 x 10.5 inches and meant for a pet of 16 lb or less, measuring no more than 16 inches long and 9.5 inches tall. Sherpa’s description adds that its spring wire frame lets the rear flatten by several inches under a low seat.
Sherpa calls it airline approved and part of its Guaranteed On Board program without naming any airline. The listing mentions mesh panels but not how many sides, and American asks for mesh on three or more, so look at the photos before you order.
Seller on 3 November 2026: Amazon.com. Mesh: not stated. The dimensions and pet limit are the listing’s word, not a measurement.
Lekereise Top-Expandable Pet Carrier
Exactly at the limit
Best for: travellers on a budget with a pet of 15 lb or less, on mainline jets.
Level with American’s limit on all three sides, so there’s no margin at all.
Outside 18 x 11 x 11 in · pets to 15 lb · bag 2.78 lb · $21.99 on 3 November 2026
Full details
Its Amazon title claims approval from Delta, United and American, which is the seller talking, and it still suggests confirming the size with your airline. Inside, it’s built for a pet no bigger than 17 x 10 x 10 inches, and the mesh wraps five sides. Only eight were left when I opened it.
Unzip the roof and it gains 3.9 inches of headroom, which is for the hotel room, not the cabin. Its sibling, ASIN B0G4M3W62D, uses mesh on three sides only, weighs 2.6 lb and cost $59.99 on 3 November 2026.
Seller on 3 November 2026: Syroad. Mesh: five sides. The dimensions and pet limit are the listing’s word, not a measurement.
Two I left out
The SturdiBag Pro I looked at opens on its Medium size, which the listing gives as 15 x 12 x 11.75 inches. That’s an inch too wide and three quarters of an inch too tall for American’s soft-sided limit.
The small Sherpa Original Deluxe would have been a lovely regional-jet pick at 15 x 10 x 8.5 inches, but the Amazon listing was unavailable when I last looked, so I haven’t linked it.
Where you can sit with your pet
Seat choice matters as much as the carrier, because some rows simply have nowhere to put it.
Pets can’t sit in bulkhead or exit rows on any American plane. There’s no room for them in First or Business on the 777s and 787s, and only smaller soft carriers fit in Business on the three-cabin A321T.
Booking your pet and the day you fly
- Add your pet right after you book: find the trip on aa.com or in the American app, choose “Add carry-on pets” under Additional Services and pick the flights. Space goes first come, first served.
- Pay at the ticket counter on the day, where an agent checks your pet and carrier. American takes cards or paper vouchers, not cash or checks.
- Bring a stroller? It goes in as a checked bag at the counter, with the usual bag fee.
- On board, the carrier stays closed under the seat in front of you until you land.
If your dog has never spent an hour zipped in a bag, start practising at home a few weeks ahead, and borrow the tips in our calm-flying guide.
Routes where pets can’t ride in the cabin
American flies pets on most routes up to 12 hours, but a handful of destinations are off the list for carry-on pets.
Hawaii is the one that surprises people most. If the islands are the plan, read how to take a dog to Hawaii and skip quarantine, which names the carriers that still accept pets on those routes.
Too big for the cabin?
American only checks pets for active-duty US military and State Department Foreign Service staff on official orders. Everyone else with a larger dog has to use American Airlines Cargo or another airline.
Our breakdown of what it costs to ship a dog compares those options, and the American Airlines pet policy guide has the rest of the airline’s rules.
How I chose these
I started from American’s carrier rules, then opened each Amazon listing and brand page and wrote down sizes, weight limits, mesh, prices and sellers exactly as they were published.
None of these bags has travelled with me, and nobody inside one can report back, so comfort is something I can’t vouch for. Star ratings stayed out too, because a five-star bag can still be an inch too tall. More on the way these guides are put together.
Choosing the right size for your pet
Begin with the animal rather than the bag. Your cat or dog should be able to get up, turn in a circle and settle again without touching the fabric, and the weight rating should sit comfortably above its real weight.
Then think about your routes. On mainline jets anything inside 18 x 11 x 11 inches meets the rule, but if your itinerary includes an Eagle flight, a carrier an inch or two smaller gives you room for a tight seat.
Finally, count the mesh sides in the photos, since American asks for three or more, and book your pet early, especially around the holidays. Our holiday pet embargo guide covers what US airlines restrict in late November and December.
Flying other airlines too? The same carriers are measured against Delta’s and United’s rules in our Delta carrier guide and United carrier guide.
Frequently asked questions
Does American Airlines weigh pet carriers?
Only on the three-cabin Airbus A321T, where staff weigh your pet and its bag at check-in and the two together must stay under 20 lb (9.07 kg). On every other American aircraft there’s no published weight cap for a pet in the cabin.
Can I bring a carry-on bag as well as my pet on American?
One extra item only. Next to the pet carrier you can take either a personal item such as a handbag or a carry-on that fits the overhead bin, never both.
Do I pay the pet fee again on a connection?
Only on a long one. The $150 covers each direction, but a stopover or connection of four hours or more means the fee applies again for each segment.
What if part of my trip is on a partner airline?
American doesn’t collect pet fees for flights another airline operates, even with an American flight number. Look for “Operated by” on your ticket, then check in and pay with that airline, under its own pet rules.
How old does my puppy or kitten have to be to fly with American?
At least 8 weeks old for flights within the US and Puerto Rico. Pets can’t be sedated or tranquilized, which American says follows advice from the American Veterinary Medical Association.
Want the source? Here is American’s pet travel page.
The Nomad Paws is in memory of Woody, a great traveler and, most of all, the best, kindest and wisest friend I have ever had.
I built this from American’s pet page, the Petsfit and Sherpa brand pages and five Amazon listings, all opened on 3 November 2026. It’s a desk comparison of published numbers, not a hands-on test, so a tape measure on the real bag is the final word.
As an Amazon Associate I earn from qualifying purchases made through the buttons above. Gate agents make the call on the day, so check American’s page again close to your flight. Nothing here is veterinary advice, and a nervous flyer is one to talk over with your vet first.
