Gear · comparison

Best Pet Carrier Backpack 2026: Picks, Sizes and Airline Fit

Our picks, by trip, with prices from the makers' and sellers' pages on 12 October 2026. Plain links: we earn nothing from them.

Hikes and trailsK9 Sport Sack Air 2$99.95 · dogs up to 25 lbForm-fitting mesh sides; sized by collar-to-tail length

Illustration of the Sherpa Original Deluxe carrier

US cabin, in stockSherpa Original Deluxe M$69.99 · pets up to 16 lbSoft-sided, not a backpack: fits 18 × 11 × 11 in; mesh sides not stated

Illustration of the Mr. Peanut’s Monterey Horizontal Backpack

Lufthansa, 8 kg ruleMr. Peanut’s Monterey M$139 · pets up to 14 lb thereWithin 55 × 40 × 23 cm; 3.6 lb of bag leaves 14 lb for the pet

Illustration of the PetAmi Deluxe 2-Way Entry Backpack

Small budget, townPetAmi Deluxe$40.99 · pets up to 18 lb3 mesh windows, 2 doors; its 12.5 in side is over US under-seat limits

Pictures are illustrations drawn from the makers' product photos, not photos of the products.

The Armarkat Backpack ($64.99, 17 × 11 × 11 in) is the one backpack we found within 18 × 11 × 11 in, but PetSmart showed it out of stock on 12 October 2026, so the in-stock pick for US cabins is the soft-sided Sherpa.

FG TeamFurry Guardian editorial teamOctober 12, 2026

Prices checked12 Oct 2026 · on the makers' pages

K9 Sport Sack AirTrail$99.9525 lbSize not published, so no airline checkNo size

K9 Sport Sack Air 2. $99.95 in all four sizes, rated for 25 lb. Walks, hikes and transit with a dog up to 25 lb.

Size: Sized by collar-to-tail length (9 to 22 in); no bag size published. Bag weight: not published.
Airflow: Mesh side panels. For hikes: form-fitting mesh sides and a design made for walks, hikes and bike rides.
Limit: Sized by collar-to-tail length; no bag size published. No cabin claim and no bag size, so no airline fit can be checked.

K9 Sport Sack Air on the maker's page

PetAmi DeluxeTown$40.9918 lb16.3 × 12.5 × 10.2 in41 × 32 × 26 cm✗ over✗ overRegional jets †

PetAmi Deluxe 2-Way Entry Backpack. $40.99, rated for 18 lb. The low-cost pick for cats and small dogs in town.

Size: 16.3 × 12.5 × 10.2 in (41 × 32 × 26 cm), longest side first (maker: 12.5 × 10.2 × 16.3 in). Under-seat: Delta, United and American over; Lufthansa over; Air Canada regional jets only †. Bag weight: not published.
Airflow: 3 mesh windows, 2 side doors.
Maker's airline wording: “Airline Approved: Yes”. That is the maker's claim, not an airline approval.
Limit: Bag weight not published. Its 12.5 in middle side is over the 11 in of US under-seat limits.

PetAmi Deluxe on the maker's page

Monterey MediumCabin$139~16 lb18.9 × 11.4 × 9 in48 × 29 × 23 cm✗ over✓ fitsRegional jets †

Mr. Peanut’s Monterey Horizontal Backpack, Medium. $139, rated for about 16 lb. Flying: the pet lies flat, and it converts to an under-seat bag.

Size: 18.9 × 11.4 × 9 in (48 × 29 × 23 cm), longest side first (maker: 18.9 × 11.4 × 9 in on its side). Under-seat: Delta, United and American over; Lufthansa fits; Air Canada regional jets only †. Bag weight: 3.6 lb, so up to 14 lb of pet under the 8 kg rule.
Airflow: Mesh on 4 sides, opens at both ends. For hikes: a horizontal pod the maker designs for biking, travel and hiking.
Maker's airline wording: “Airline Compliant”; Medium “excellent for in-cabin airline use”. That is the maker's claim, not an airline approval.
Limit: The maker does not say if its sizes are inside or outside the bag. At 18.9 in it is long for under-seat limits of 18 in or less.

Monterey Medium on the maker's page

Monterey LargeCabin$154~24 lb19.7 × 12.6 × 9.8 in50 × 32 × 25 cm✗ over✗ overRegional jets †

Mr. Peanut’s Monterey Horizontal Backpack, Large. $154, rated for about 24 lb. Bigger cats and small dogs on long-haul aircraft.

Size: 19.7 × 12.6 × 9.8 in (50 × 32 × 25 cm), longest side first (maker: 19.7 × 12.6 × 9.8 in on its side). Under-seat: Delta, United and American over; Lufthansa over; Air Canada regional jets only †. Bag weight: 3.9 lb, so up to 13.7 lb of pet under the 8 kg rule.
Airflow: Mesh on 4 sides, opens at both ends.
Maker's airline wording: Maker: Large is “best used for transcontinental and international routes only”. That is the maker's claim, not an airline approval.
Limit: Heavier and longer than the Medium. The maker says Large is for long-haul aircraft only.

Monterey Large on the maker's page

Kurgo G-TrainTrail$144.9525 lb21 × 13 × 10 in53 × 33 × 25 cm✗ over✗ overRegional jets †

Kurgo G-Train Dog Carrier Backpack. $144.95, rated for 25 lb. Day hikes: hip belt, sternum strap, gear pockets.

Size: 21 × 13 × 10 in (53 × 33 × 25 cm), longest side first (maker: 13 × 21 × 10 in). Under-seat: Delta, United and American over; Lufthansa over; Air Canada regional jets only †. Bag weight: not published.
Airflow: Mesh back, sides and zip-open top. For hikes: hip belt, sternum strap and gear pockets for day hikes.
Limit: Top entry only. Built for the trail, not for under a seat.

Illustration of the Kurgo G-Train Dog Carrier Backpack, drawn from the maker's photos; not a photo of the product.

Kurgo G-Train on the maker's page

Sherpa ElevationTrail$76.9916 lb19 × 13 × 9 in48 × 33 × 23 cm✗ over✓ fitsRegional jets †

Sherpa Elevation Pet Backpack, Medium. $76.99, rated for 16 lb. Claw-proof mesh and an ice-pack pocket for warm hikes.

Size: 19 × 13 × 9 in (48 × 33 × 23 cm), longest side first (maker: 9 × 13 × 19 in). Under-seat: Delta, United and American over; Lufthansa fits; Air Canada regional jets only †. Bag weight: 4 lb, so up to 13.6 lb of pet under the 8 kg rule.
Airflow: Wire-mesh panels and window. For hikes: claw-proof mesh and an ice-pack pocket for warm hikes.
Limit: 19 in tall; for pets up to 18 in high and 12 in long. Sherpa makes no airline claim for it.

Illustration of the Sherpa Elevation Pet Backpack, drawn from the maker's photos; not a photo of the product.

Sherpa Elevation on the maker's page

Petsfit ExpandableTown$50.9922 lb16.5 × 13.8 × 11 in42 × 35 × 28 cm✗ over✗ over✗ over

Petsfit Expandable Backpack Carrier. $50.99 (green), rated for 22 lb. Vet trips and long waits: the side expands into a lounge.

Size: 16.5 × 13.8 × 11 in (42 × 35 × 28 cm), longest side first (maker: 13.8 × 11 × 16.5 in (expands to 24.3 in long)). Under-seat: Delta, United and American over; Lufthansa over; Air Canada over. Bag weight: not published.
Airflow: Mesh on 4 sides; expands at rest.
Limit: Bag weight not published.

Illustration of the Petsfit Expandable Backpack Carrier, drawn from the maker's photos; not a photo of the product.

Petsfit Expandable on the maker's page

Armarkat BackpackCabinOut of stock, 12 Oct$64.9920 lb17 × 11 × 11 in43 × 28 × 28 cm✓ fits✗ over✗ over

Armarkat Backpack Pet Carrier (PetSmart). $64.99 at PetSmart, rated for 20 lb. The one backpack we found within 18 × 11 × 11 in (Delta, United, American).

Out of stock: PetSmart showed it out of stock on 12 October 2026. In stock that day and also within 18 × 11 × 11 in: the soft-sided Sherpa Original Deluxe, Medium ($69.99, 17 × 11 × 10.5 in, pets up to 16 lb), though Sherpa does not say how many sides are mesh.

Size: 17 × 11 × 11 in (43 × 28 × 28 cm), longest side first (maker: 17 × 11 × 11 in). Under-seat: Delta, United and American fit; Lufthansa over; Air Canada over. Bag weight: 2.3 lb, so up to 15.3 lb of pet under the 8 kg rule.
Airflow: Ventilation panels (sides not stated).
Maker's airline wording: PetSmart: “Meets Airline Travel: Yes”. That is the maker's claim, not an airline approval.
Limit: Sold by PetSmart; no maker page found. PetSmart’s airline wording is a seller claim, not an airline approval.

Illustration of the Armarkat Backpack Pet Carrier, drawn from the maker's photos; not a photo of the product.

Armarkat Backpack on the seller's page

K9 KolossusTrail$259.9580 lbSize not published, so no airline checkNo size

K9 Sport Sack Kolossus. $259.95, rated for 80 lb. Carrying a medium or large dog out on a trail.

Size: No bag size published; 60 L of gear space. Bag weight: not published.
Airflow: Not stated. For hikes: a 60 L backpacking pack built to carry a medium or large dog.
Limit: A rescue and backpacking pack, not a travel carrier.

Illustration of the K9 Sport Sack Kolossus, drawn from the maker's photos; not a photo of the product.

K9 Kolossus on the maker's page

Only the Armarkat (17 × 11 × 11 in) is within the 18 × 11 × 11 in of Delta, United and American, and it was out of stock on 12 October 2026. † Fits only Air Canada’s Dash 8, E175 and CRJ900 (55 × 40 × 27 cm), not its other jets (43 × 40 × 20 cm). All three sides compared in any orientation, from the maker, seller and airline pages read 12 October 2026; researched, not tested with a pet. Open a row for the details.

Find the backpack that fits your pet and your flight

Weight, airline size and the 8 kg rule are hard limits: a bag that breaks one is never your pick. We only say a bag fits an airline when both publish their numbers.

Example, not your answers

A 12 lb cat on Lufthansa, up to $160: Mr. Peanut's Monterey Medium, $139. All three sides fit 55 × 40 × 23 cm, and its 3.6 lb plus the cat makes 15.6 lb, within 8 kg.

Method: we read each maker's or seller's page for price, rated pet weight, size, bag weight and airflow, and each airline's page for its under-seat limit, on 12 October 2026, then compared all three sides of each bag in any orientation. These are researched picks; we have not tested the bags with a pet.

Which pet carrier backpack should you buy?

Start from your pet's weight: a bag is only a candidate if the maker rates it for at least that much. For walks and trails, the K9 Sport Sack Air ($99.95, 25 lb) and the Kurgo G-Train ($144.95, 25 lb, hip belt) carry the most; for a large dog, only the K9 Kolossus (80 lb). For flying, size decides: pick your airline below to see every side of every bag against its limit.

Every side of each backpack against the under-seat limit you choose

United: 18 × 11 × 11 in soft-sided (10 in tall on 737 MAX)

Armarkat Backpack ✓ fits

Longest 17 in

Middle 11 in

Shortest 11 in

Mr. Peanut’s Monterey M ✗ longest side 0.9 in over, middle side 0.4 in over

Longest 18.9 in

Middle 11.4 in

Shortest 9 in

PetAmi Deluxe ✗ middle side 1.5 in over

Longest 16.3 in

Middle 12.5 in

Shortest 10.2 in

Mr. Peanut’s Monterey L ✗ longest side 1.7 in over, middle side 1.6 in over

Longest 19.7 in

Middle 12.6 in

Shortest 9.8 in

Sherpa Elevation ✗ longest side 1 in over, middle side 2 in over

Longest 19 in

Middle 13 in

Shortest 9 in

Petsfit Expandable ✗ middle side 2.8 in over

Longest 16.5 in

Middle 13.8 in

Shortest 11 in

Kurgo G-Train ✗ longest side 3 in over, middle side 2 in over

Longest 21 in

Middle 13 in

Shortest 10 in

Within the limitOver the limitLimit for that side

Against United’s 18 × 11 × 11 in soft-sided, 1 of 7 backpacks with a published size fit: Armarkat Backpack. Closest of the rest: Mr. Peanut’s Monterey M, longest side 18.9 in against 18 in and middle side 11.4 in against 11 in. Drawings: the front of each bag to one scale, inside a dashed outline of the limit's two longest sides turned the same way; the bars give all three sides. K9 Sport Sack Air and K9 Kolossus publish no size. Sides compared longest to shortest, in any orientation, from the maker, seller and United pages read 12 October 2026.

How heavy a pet each backpack carries, against the 8 kg cabin rule

Max pet weightEmpty bag, where published

Pet and bag together must stay under 8 kg (17.6 lb) at Lufthansa, KLM and Air France: with its 3.6 lb bag, the Monterey Medium leaves room for a pet up to 14 lb, and the 2.3 lb Armarkat up to 15.3 lb. US airlines publish a size limit, not a weight limit.

Can a pet carrier backpack go in an airline cabin?

Only if the closed bag fits the operating airline's under-seat limit, and on Lufthansa, KLM and Air France, only if pet and bag together stay under 8 kg. "Airline approved" on a maker's or seller's page is their claim; the airline decides at the gate. Delta's 18 × 11 × 11 in is a recommendation that fits most of its aircraft, and Delta says the real maximum depends on the aircraft⁸.

Under-seat limits and pet fees of 13 airlines

Airline	Under-seat carrier limit	Pet fee
Delta	18 × 11 × 11 in (recommended; depends on aircraft)	$150 one way in the US and Canada, $200 international
United	18 × 11 × 11 in soft-sided (10 in tall on 737 MAX)	$150 each way
American	18 × 11 × 11 in soft-sided	$150 per kennel
Alaska	17 × 11 × 9.5 in soft-sided	$100 each way
JetBlue	17 × 12.5 × 8.5 in	$150 each way
Air Canada (most mainline jets)	43 × 40 × 20 cm soft-sided, no hard plastic windows	CA$50 to CA$60 in Canada and to the US, CA$100 to CA$120 international
Air Canada (Dash 8, E175, CRJ900)	55 × 40 × 27 cm soft-sided, no hard plastic windows	CA$50 to CA$60 in Canada and to the US
Lufthansa	55 × 40 × 23 cm soft-sided, 8 kg with the pet	Set per route
KLM	46 × 28 × 24 cm, 8 kg with the pet	€70 to €500 one way
Air France	Size not shown on the pages we read; 8 kg with the pet	US to Europe $225
Southwest	Size not shown on the pages we could read	$125 one way on the mainland
British Airways	No pets in the cabin on any route	Hold only
Emirates	No pets in the cabin (guide dogs and some falcons excepted)	Hold only

Each airline's own page, read 12 October 2026. The operating airline decides at the gate.

Three rules catch people out. Air Canada takes soft-sided carriers only and refuses backpacks with hard plastic windows, which rules out bubble backpacks¹³. United limits carriers to 10 in tall on the 737 MAX⁹. British Airways and Emirates carry no pets in the cabin at all^18,19, so a backpack cannot fly with you there; see our crate guide for the hold. Route by route, our airline pet policies guide has the details.

What if no backpack fits your airline?

Switch to a soft under-seat carrier for the flight; they are built lower than backpacks. The Sherpa Original Deluxe Medium ($69.99, 17 × 11 × 10.5 in, pets up to 16 lb, in stock on 12 October 2026) is within the 18 × 11 × 11 in of Delta, United and American²⁵; the Small (15 × 10 × 8.5 in, 8 lb), which also fits Alaska, JetBlue, KLM and Lufthansa, was sold out that day²¹. Sherpa publishes neither the bag weight for the 8 kg rule nor how many sides are mesh. With ventilation on 3 sides, as Delta and American ask, the Mr. Peanut's Gold Series Mini (17 × 11 × 9 in closed, $134, 15 lb)²³ and the Sleepypod Atom (17 × 10.5 × 8.5 in, $139.99, 12 lb)²⁴ do the same. Air Canada's 20 cm height is the hardest: the Sherpa Luxe Tote Medium (43 × 30.4 × 19 cm, $64.99, 16 lb) fits it lying on its side²². A pet too heavy for any of them flies in the hold, in a rigid crate.

Illustration of the Sherpa Luxe Tote — Illustrations drawn from the makers' product photos, not photos of the carriers. Sizes, ratings and stock are in the paragraph above.

How do you size a backpack for your pet?

Use the maker's own method, not the bag's letter size. K9 Sport Sack sizes the Air by the length from collar to the base of the tail, 9 to 22 in across its four sizes, all rated for 25 lb¹. Sherpa rates the Elevation for pets of 16 lb or less that measure up to 18 in high and 12 in long⁶. For flying, weigh your pet, add the empty bag, and measure the closed bag yourself on all three sides: Mr. Peanut's does not say whether its sizes are inside or outside the bag.

Frequently asked questions

Are backpack carriers good for dogs?

Yes, for small dogs within the bag's rated weight: 25 lb for the K9 Sport Sack Air and the Kurgo G-Train, 80 lb for the K9 Kolossus built for medium and large dogs. In warm weather, choose mesh on 3 sides or more, such as the Kurgo or the Petsfit Expandable.

Which pet carrier backpack is airline approved?

None is approved by an airline in advance; the operating airline decides at the gate. Mr. Peanut's calls its Monterey "Airline Compliant", PetAmi says "Airline Approved: Yes" and PetSmart lists the Armarkat as meeting airline travel. Of the nine we priced, only the Armarkat is within Delta, United and American's 18 × 11 × 11 in on every side, and only the Monterey Medium and the Sherpa Elevation are within Lufthansa's 55 × 40 × 23 cm.

What is the best pet carrier backpack for a large dog?

The K9 Sport Sack Kolossus, rated for dogs up to 80 lb at $259.95, is the only backpack on our list made for medium and large dogs². It is a trail and rescue pack, not a travel carrier.

How much weight can a pet carrier backpack hold?

Between 15 and 25 lb for most: 16 lb for the Sherpa Elevation and Mr. Peanut's Monterey Medium, 18 lb for the PetAmi Deluxe, 20 lb for the Armarkat, 22 lb for the Petsfit Expandable, 25 lb for the K9 Air and the Kurgo G-Train. Never put a pet heavier than the maker's rating in the bag.

For trail days, pair the bag with our dog carrier for hiking guide and a GPS tracker with no subscription. Moving abroad? Start with the Canada entry rules or our expat pet insurance comparison.

Written by the FG Team, the Furry Guardian editorial team, who keeps these border rules current.

Sources, all read October 12, 2026

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