SHORT ANSWER

TAP Air Portugal and Azores Airlines are currently the only airlines flying nonstop from the US to Portugal that will carry a dog or cat in the cabin or in the aircraft hold as standard passenger baggage. United and Delta will carry small pets in the cabin only, with no general-public option for a pet too large to fly under the seat. American Airlines does not allow carry-on pets on any trans-Atlantic route, including its new Philadelphia to Porto service, so a pet flying with American to Portugal has to move through American Airlines Cargo instead. The airline you book determines whether your pet can travel with you at all, so this decision has to happen before you lock in flights, not after.

Why the Airline You Book Decides Whether Your Pet Can Travel at All

Most pet owners start planning a move to Portugal by researching import paperwork: the EU health certificate, the microchip and vaccination sequence, the Lisbon Airport arrival process. All of that matters, but it assumes your pet can get on the plane in the first place. That assumption doesn't hold across every airline serving this route. Some airlines will only take a pet if it's small enough to sit under your seat. Others have closed their pet cargo programs to the general public entirely, following a wave of policy changes across the industry in recent years. Picking an airline for a Portugal move is really picking a pet transport policy, and those policies differ enough to change your entire plan.

TAP Air Portugal: The Only Full-Service Option on This Route

TAP Air Portugal is Portugal's flag carrier and the airline with the broadest nonstop US network into Lisbon and Porto, including established routes from Boston and Newark and newer or expanding service from cities including Orlando. TAP is also the only major airline on this route that offers a genuine cargo hold option for pets alongside cabin transport, which matters if your dog is larger than a small lapdog.

For cabin travel, TAP requires a soft-sided carrier that closes securely, sets a combined pet-and-carrier weight limit of 8 kg (17 lbs), and requires pets to be at least 10 weeks old. TAP explicitly reserves the right to move a pet to the hold if the carrier exceeds size or weight limits at check-in, so it's worth weighing your pet and carrier together before you book, not after.

For hold travel, the weight allowance depends on the route. On flights to, from, or connecting through the US, the maximum combined weight of pet and carrier is 32 kg (70 lbs); on TAP's European and other international routes, that limit rises to 45 kg (99 lbs). A larger dog moving from the US to Portugal on TAP needs to fit inside that lower 32 kg ceiling, which is worth confirming directly with TAP before booking if your dog is close to that line.

TAP also publishes a specific list of brachycephalic (flat-faced) breeds, including bulldogs, pugs, Shih Tzus, and Persian cats, that are not accepted in the hold unless a veterinary certificate confirms the animal does not display the airway-narrowing traits typical of its breed. Separately, TAP requires a reinforced CR82-style container for five breeds it classifies as potentially dangerous: the Fila Brasileiro, Argentine Mastiff (Dogo Argentino), Pit Bull Terrier, Rottweiler, and Tosa Inu, when six months or older. None of this is a ban on these breeds. It's a documentation and equipment requirement that needs to be sorted out well ahead of departure.

As Adam Melton, VP of Strategic Initiatives at Starwood Pet Travel, puts it: "TAP is the airline most families end up choosing for Portugal moves precisely because it doesn't force a choice between the size of your pet and whether they can fly with you. But that flexibility comes with more rules to track, not fewer. The families who read the mandatory conditions list before they book are the ones who don't get a surprise at the check-in counter."

Azores Airlines: The Overlooked, More Affordable Alternative

Azores Airlines (SATA) connects the US to mainland Portugal through the Azores, typically via Boston or Providence, and it is worth serious consideration for pet owners because its pet policy is both flexible and comparatively inexpensive. Azores Airlines accepts pets in the cabin up to 8 kg (17 lbs) for a flat fee of 35 EUR, and it accepts larger pets in the aircraft hold with the transport cost generally absorbed into the passenger's standard checked baggage allowance up to 45 kg (100 lbs), with additional per-kilogram charges only if that allowance is exceeded. That pricing structure is notably lower than the flat per-kennel service fees charged by other carriers on this route.

Azores Airlines does carry some added complexity of its own. Pets aged 8 weeks or younger, pregnant animals, and animals traveling with unaccompanied minors or wheelchair-assistance passengers are restricted from the cabin. Because most Azores Airlines itineraries connect through Ponta Delgada, the total travel time and number of touch points for your pet is typically longer than a nonstop TAP flight, which is worth factoring in for an older pet or one who doesn't do well with connections.

United Airlines: Cabin-Only, With No General-Public Hold Option

United flies nonstop from Newark to Lisbon, and it is a straightforward choice for pet owners with a small dog or cat that can travel under the seat. United charges $150 each way for a pet ticket, allows the pet to stay in a carrier without an explicit weight or breed limit, and permits up to two pets per traveler on most aircraft (with some smaller aircraft types limited to one pet per person due to under-seat space).

The limitation is more serious than the cabin size requirement itself: United ended its general-public PetSafe cargo program, and pets can now only travel in United's cargo hold if the traveler is active-duty military or a State Department Foreign Service employee moving on official orders. There is no route to fly a large dog to Portugal on United outside of those two categories. If your pet doesn't fit safely and comfortably in an under-seat carrier, United isn't currently an option for your move.

Delta Air Lines: Cabin-Only, With a Notable Route Expansion Ahead

Delta serves this market from New York-JFK and Boston to Lisbon, and has recently announced a new nonstop route connecting JFK to Porto beginning in 2026 (worth reconfirming closer to your travel date, since new routes can shift before launch). Like United, Delta only carries pets in the cabin for the general public, at a fee of $200 each way for international travel. Delta's kennel must fit fully under the seat in front of the traveler, and Delta maintains a published list of destinations where in-cabin pets aren't accepted at all; Portugal is not on that exclusion list, so cabin travel is a viable option for pets small enough to qualify.

Delta Cargo, the airline's separate pet shipping service for animals too large for the cabin, currently has a temporary global embargo on household pet shipments for the general public, with a limited exception for active-duty military and Foreign Service Officers moving on orders. In practice, that puts Delta in the same position as United for larger pets: a small cabin-eligible pet can fly, but there is currently no general-public path for a pet requiring hold or cargo transport.

American Airlines: No Carry-On Pets on Any Trans-Atlantic Route

American Airlines has recently expanded its Portugal footprint with new nonstop service to Porto, but the airline's own policy is explicit and worth reading closely: American does not allow carry-on pets on trans-Atlantic trips of any kind. This isn't a Portugal-specific restriction, it applies to every American Airlines flight crossing the Atlantic, regardless of flight duration or destination.

For pet owners flying American to Portugal, there are two paths. Active-duty military and State Department Foreign Service personnel moving on official orders can check a pet at the ticket counter for $200 per kennel. Everyone else needs to book through American Airlines Cargo's PetEmbark service, a separate cargo shipping process from a standard passenger booking, with its own scheduling, documentation, and fee structure that is confirmed at the time of booking rather than published as a flat rate. If you're planning to fly American to Portugal with a pet that isn't traveling as excess passenger baggage, build in extra lead time to coordinate the PetEmbark booking separately from your own ticket.

What Pet Owners Are Saying About Airline Choice for This Route

Airline selection comes up constantly in pet relocation communities, and the frustration is usually the same: people book their own flight first and find out about pet restrictions afterward. In a discussion thread in r/iwantout, a user planning a move from the US to Portugal wrote: "I didn't realize until after I'd already booked that my airline wouldn't take my dog in cargo anymore. Ended up having to change carriers and it cost me more in the end than if I'd just checked pet policy first" (r/iwantout discussion).

That sequencing problem is avoidable. Confirming your airline's pet policy before booking flights, not after, is the single highest-leverage step in this entire process for anyone traveling with a pet that isn't a small lapdog.

Planning Around Airline Pet Policy, Not Just Import Rules

Once you know which airlines can actually carry your pet, the rest of the relocation timeline (health certificate endorsement windows, the microchip-before-vaccine sequence, arrival notice requirements at the Point of Entry) can be built around a confirmed flight. For the full walkthrough of everything else involved in moving a pet from the US to Portugal, see our complete guide to pet relocation to Portugal. If cost is a deciding factor between airlines and transport methods, our breakdown of what it costs to import a dog versus a cat to Portugal walks through how airline fees stack up against other relocation costs.

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