Flying with Your Dog for the First Time: What Nobody Tells You

When my partner and I decided to move to Lisbon for three months with our terrier mix, Gracie, we had exactly one assumption: how hard could it be?

Reader, it was hard.

Not impossible — Gracie made it, we made it, and we'd do it again in a heartbeat. But we showed up at the airport having done just enough research to be overconfident and not quite enough to be actually prepared.

This is everything we wish we'd known.

Step One: Is Your Dog Allowed in Cabin?

This is where most people get tripped up. In-cabin travel is only available for dogs that fit (with their carrier) under the seat in front of you. The exact dimensions vary by airline, but the typical maximums are:

Carrier dimensions: ~18" × 11" × 11" (soft-sided)
Combined weight (dog + carrier): 15–22 lbs depending on airline

Gracie is 14 pounds. Her carrier is a Sherpa Original Deluxe, which is officially approved by most major US carriers and many European airlines. We researched this for two full weeks. I am not kidding.

Booking: Read Every Word

Reserve Your Pet's Spot — Immediately

Airlines limit the number of pets in cabin per flight. On most US carriers that's 4–7 pets total. You cannot just show up with a dog. You must call the airline directly to add a pet reservation — many airlines won't let you do this online.

Do this the same day you book your human tickets.

What You'll Need When You Call

Your booking confirmation number
Your dog's name, weight, and carrier dimensions
Your destination — some routes have restrictions (Hawaii requires quarantine; many Caribbean islands ban pets in cabin)

Fees

| Airline | In-Cabin Fee (Each Way) | |---|---| | United | $125 | | Delta | $95 | | American | $150 | | Southwest | $125 | | Alaska | $100 |

International routes often charge more. Check-in fees are charged per segment, not per round-trip.

The Right Carrier Is Everything

Not all soft-sided carriers are equal. The carrier must:

Fit under the seat (confirm the airline's exact dimensions)
Have ventilation on multiple sides
Have a sturdy, waterproof bottom
Allow your dog to stand, turn around, and lie down comfortably

Carriers we've used and recommend:

Sherpa Original Deluxe — fits most US carriers, machine washable, good ventilation
Sleepypod Air — great for direct overhead storage on overnight flights
Petsfit Expandable Carrier — the pop-out section is great during boarding delays

The Day Before Your Flight

Vet Documentation

For domestic US flights: Most airlines don't require a health certificate, but always check. For international flights, requirements vary significantly by destination country.

For our Lisbon trip, we needed:

EU health certificate (USDA-endorsed form)
Proof of rabies vaccination (within 1 year)
Microchip information (ISO 15-digit chip required for EU)
Tapeworm treatment administered by a vet within 5 days of arrival (UK and Ireland require this)

Start this paperwork at least 2 months before an international flight. Some certifications require USDA endorsement that takes 1–3 weeks.

The Night Before

Limit water after 8pm to reduce the chance of accidents
Feed a smaller meal than usual (avoid an empty stomach completely — it can worsen nausea)
Tire them out with a long walk or play session
Pack the carrier with their favorite blanket and a worn t-shirt of yours

At the Airport

Arrive Early

Add an extra 30–45 minutes to your normal buffer. You'll need to:

Check in with the agent (can't always do this at a kiosk with a pet)
Pay the pet fee if you haven't pre-paid
Potentially pass through a special screening process

TSA Security

Here's what nobody tells you: your dog has to come out of the carrier at security.

The carrier goes through the X-ray machine. Your dog goes through the metal detector with you — in your arms. If they panic and bolt, you're in a nightmare scenario.

Practice holding your dog through simulated chaos before the trip.

We held Gracie tight, kept her below the X-ray belt so she couldn't see the belt moving, and walked quickly. She was shaking. It took about 20 seconds. It felt like 20 minutes.

At the Gate

Once through security, Gracie came out of her carrier. We found a quiet corner, let her sniff around on-leash, gave her a long drink of water, and let her stretch. By the time we boarded she was calm.

The Flight Itself

Under the Seat Rules

The carrier goes under the seat in front of you and must stay there for the entire flight except during takeoff and landing, when it must be completely closed.

We were in seats 8C and 8D with Gracie under 8C's seat. She had just enough room, and we gave her a small treat through the mesh every 45 minutes or so.

Calming Options

Talk to your vet about options:

Adaptil (DAP) spray on the carrier bedding — we found this helped
Benadryl as a mild sedative — only with vet approval and correct dosing
Prescription medications like trazodone for very anxious dogs — ask your vet 1–2 weeks before so you can test the dose at home first

What Helped Gracie

Being slightly tired from our early wake-up
Her favorite blanket with my smell on it
A stuffed Kong that kept her occupied for the first hour
Absolutely zero food during the flight (kept her calm and prevented accidents)

Landing and Arrival

When we landed in Lisbon, Gracie perked up immediately at the new smells coming through the carrier mesh. We waited until nearly everyone deplaned before standing up — less chaos for her.

At customs, she got her first European stamp (metaphorically). The customs agent checked her EU health certificate and microchip, asked us her name and age, and waved us through in four minutes.

Then she had the longest pee of her life in the airport garden, and we took a photo of her with the Tagus River in the background.

It was completely worth every stressful moment of preparation.

The Quick Pre-Flight Checklist

[ ] Pet reservation confirmed with airline
[ ] Carrier dimensions verified for specific aircraft
[ ] Health certificate obtained (check international requirements)
[ ] Microchip info current and documented
[ ] Vaccinations up to date + records printed
[ ] Carrier training complete (dog comfortable inside)
[ ] Calming aid tested at home if using one
[ ] Collar with ID tag + current contact info
[ ] Layover plan researched (can dog leave the aircraft area?)
[ ] Destination country pet entry requirements confirmed

Flying with a dog is stressful in preparation and surprisingly calm in execution — if you've done the work. Gracie now travels like a seasoned veteran. She gets in her carrier, we say "airport?" and she walks right in.

Okay that last part is not true. But she only shakes a little now.

Safe skies — from Collin and Gracie. ✈️🐾

Flying with Your Dog for the First Time: What Nobody Tells You

Step One: Is Your Dog Allowed in Cabin?