Allegiant Air Pet Policy: The 2026 Guide (and Why It Is the Cheapest US Pet Fee)

Allegiant Air charges roughly $50 per segment to fly a small cat or dog in the cabin, frequently cited as the lowest in-cabin pet fee of any US airline. It is in-cabin only, within the contiguous 48 states, no cargo or international option. A round trip is two segments, so budget about $100 total. Confirm the current fee on Allegiant's official pet page before you book.

What the Allegiant pet fee actually costs

Allegiant's headline number is the part people remember: a pet fee of roughly $50 per segment, charged per direction of travel, according to Allegiant's traveling-with-pets page and its optional-services fee schedule. The fee is non-refundable. Always confirm the current figure directly with Allegiant before booking, because airline fees change without much notice.

The number that trips people up is "per segment." A segment is one takeoff-and-landing leg of your itinerary. A simple one-way nonstop is one segment. A round trip is two segments, so the pet fee roughly doubles to about $100 for the trip. If your routing connects through an Allegiant hub, each leg can count separately, so a connecting itinerary can run more than a nonstop one. Price the whole itinerary, not just the outbound leg, and read the fee against the number of segments shown on your confirmation.

Even doubled, that round-trip figure sits at or below what most US carriers charge for a single one-way in-cabin pet. That is why Allegiant keeps showing up at the top of "cheapest airline for pets" lists. If price is your main driver, see our broader breakdown of the cheapest way to transport a pet and how flying stacks up against ground options.

How Allegiant compares to other budget carriers

The "cheapest pet fee" claim only makes sense against the field. Here is how the three big US budget carriers line up on in-cabin pet pricing, drawing on each airline's own published policy: Frontier's traveling-with-pets page and Spirit's pet policy. Watch the unit carefully: Allegiant and Frontier price per segment (per leg), while Spirit's commonly cited figure is per direction of travel. All three are non-refundable, and all change often, so treat these as ballpark and confirm the current fee on each airline's own page before you book.

The gap is real. On a round trip, Allegiant's roughly $100 undercuts Frontier's roughly $198 and Spirit's roughly $250 by a wide margin. For the full policy detail on each, see our guides to Frontier Airlines pet transport and Spirit Airlines pet transport, both of which use a similar in-cabin-only model.

Segment vs each-way: read the fine print

Because carriers describe the same idea with different words, two airlines that look similar on paper can diverge once you add a connection. "Each way" or "per direction" usually means one charge per outbound and one per return, regardless of connections. "Per segment" means one charge per flight leg, so a connection can add a charge. On a nonstop round trip the two phrasings produce the same count, two charges. Add one connection and a per-segment carrier can charge for three or four legs. When you compare quotes, normalize everything to the actual number of legs on your itinerary.

If you are still weighing cabin against the cargo hold for a larger dog, note that Allegiant does not offer a cargo pet program at all, so the choice is in-cabin on Allegiant or a different carrier entirely.

Carrier size limits and what counts as a carry-on

Allegiant allows one pet carrier in the cabin, and the carrier counts as one of your two allowed carry-on items, according to Allegiant's pet policy. There is no separate "personal item plus pet" allowance: the carrier is the bag. The published maximum dimensions are roughly:

• Soft-sided carrier: about 18 inches long by 12 inches wide by 11 inches high.
• Hard-sided carrier: about 17 inches long by 11 inches wide by 10.5 inches high.

Soft-sided bags get slightly larger maximums because they flex under the seat. Confirm the exact current dimensions on Allegiant's official page before you buy a carrier, since published limits are revised periodically. The hard requirement underneath the numbers: your pet must be able to stand up and turn around comfortably inside, and the carrier must fit fully under the seat in front of you. For help choosing a bag that meets these limits, see our roundup of the best airline-approved dog carrier options.

One rule Allegiant enforces strictly: the pet must stay fully inside the carrier the entire time, both in the terminal and onboard. You do not get to walk your dog through the gate area out of the bag, and the carrier stays zipped under the seat for the whole flight. Plan a bathroom break before you reach security, because once you are airside the pet stays in the carrier.

Who can actually fly and where

Allegiant's pet program is deliberately narrow, and the limits are where most surprises happen. According to the airline's pet policy:

• Species: small domestic cats and dogs only.
• Size: small enough to fit in an approved under-seat carrier and remain comfortable. There is no in-cabin option for a dog too large for the carrier.
• Geography: travel within the contiguous 48 states only. Allegiant restricts pet travel to international destinations and US territories, so Hawaii, Puerto Rico, and routes outside the lower 48 are generally not available for pets.
• Cabin only: there is no checked-baggage or cargo pet service.

If you have a large dog, an international move, or a flight to a US territory, Allegiant is the wrong tool. You will need a carrier with a cargo program or a ground transport operator instead. For a sense of the full range of options and what they cost, see how much pet transport costs and the airlines hub linked below.

A quick real-world cost example

Say you are flying a 10-pound terrier from Las Vegas to Orlando and back, both legs nonstop, which is the kind of point-to-point leisure route Allegiant is built around. That is two segments, so the pet fee is roughly $50 plus roughly $50, about $100 total, on top of your fare. The same round trip on Spirit at about $125 each way would run roughly $250 in pet fees, and on Frontier at about $99 per segment roughly $198. The carrier slides under the seat as one of your two carry-on items, so there is no extra bag charge for it. Those figures are approximate and non-refundable; confirm the current fee with each airline before booking, since a fee change can shift the math.

Service dogs and emotional support animals

The rules here changed for everyone, not just Allegiant. Trained service dogs travel in the cabin free of charge with the required documentation, under the Air Carrier Access Act. Airlines, including Allegiant, generally ask you to submit the US Department of Transportation's service animal forms in advance.

Emotional support animals no longer have special protection. Following a US Department of Transportation rule that took effect in January 2021, ESAs are no longer required to be accommodated as service animals, per the DOT's service animal guidance. In practice that means an emotional support animal now flies as a regular in-cabin pet, subject to the standard fee, carrier rules, and size limits described above. If your animal qualifies as a trained service dog, confirm the current documentation requirements directly with Allegiant before booking, because the forms and deadlines are set by the airline.

Who Allegiant suits, and who should look elsewhere

Allegiant is a strong fit for a specific traveler and a poor fit for others. Use this quick decision framework before you book.

Allegiant works well if

• You have a small dog or cat that fits an under-seat carrier.
• You are traveling within the lower 48 states.
• Price is your top priority and you want the lowest in-cabin pet fee available.
• You can fly a nonstop or limited-connection route Allegiant serves, which keeps the per-segment fee down.

Look elsewhere if

• Your dog is too big for an under-seat carrier; you will need a cargo program or ground transport.
• You are flying internationally, to Hawaii, or to a US territory.
• Your itinerary has several connections; the per-segment fee can erode the savings.
• You need flexibility; Allegiant's limited schedule and point-to-point network mean fewer rebooking options if a flight is canceled.

Booking and day-of-travel tips

A little planning keeps the low fare from turning into a stressful gate experience.

• Add the pet during booking or by phone. Cabin pet space is limited per flight, so reserve early rather than showing up and hoping.
• Measure your carrier against the published limits before you leave home, and confirm those limits on Allegiant's site that week.
• Arrive early. Pets are typically checked in at the airport counter, not at a kiosk, so build in extra time.
• Walk and water your pet before security. Once airside, the pet stays zipped in the carrier.
• Skip the food right before the flight to reduce the chance of an upset stomach; a thirsty pet is easier to manage than a nauseous one.
• Bring documentation. Some origin or destination airports request proof of vaccination; carry a current rabies record to be safe.

How we sourced this

The fees, carrier dimensions, and travel restrictions above are drawn from Allegiant's official traveling-with-pets page and its optional-services fee schedule, cross-checked against the published in-cabin pet policies of Frontier and Spirit for the comparison table. The service-animal rules reference the US Department of Transportation's Air Carrier Access Act guidance. Airline pet fees and carrier limits change frequently and vary by routing, so every figure here is presented as approximate. Confirm the current fee, carrier dimensions, and route eligibility directly with Allegiant before you book.

For policies on other carriers and a full breakdown of cabin rules, fees, and crate requirements across the industry, start at our pet airlines hub.