Your crate or carrier is the one thing you fully control when flying with a pet, and getting it wrong is the fastest way to get denied at check-in. The right carrier depends on three things: whether your pet flies cabin or cargo, your airline's specific dimensions, and your pet's exact size. This guide covers everything from soft-sided cabin carriers to IATA-compliant cargo crates, with airline-by-airline comparisons, sizing formulas, and model recommendations.
In this guide
- 1. Cabin vs. Cargo: Which Carrier Do You Need?
- 2. Cabin Carrier Dimensions by Airline
- 3. Soft-Sided vs. Hard-Sided Cabin Carriers
- 4. IATA Cargo Crate Requirements
- 5. IATA Crate Sizing Chart
- 6. How to Measure Your Pet
- 7. Crate Training: The Non-Negotiable Step
- 8. Common Mistakes That Get You Rejected at Check-In
- 9. Frequently Asked Questions
- 10. Get Your Carrier Checked Before You Fly
1. Cabin vs. Cargo: Which Carrier Do You Need?
This is determined by your pet's weight, including the carrier:
- Under 8–10 kg (pet + carrier): Cabin. Use a soft-sided or hard-sided carrier that fits under the seat in front of you.
- Over 10 kg: Cargo. Use a rigid IATA-compliant crate.
- Over 32 kg: Dedicated cargo pet program (United PetSafe, Lufthansa Cargo). Same IATA crate, different booking process.
Some airlines don't offer cabin at all (British Airways, Emirates) and some don't offer cargo (Delta, American). Check your airline's policy before buying anything.
2. Cabin Carrier Dimensions by Airline
Every airline has different maximum dimensions. Buy the carrier AFTER checking your airline, not before.
| Airline | Max L × W × H (cm) | Max weight |
|---|---|---|
| Air France | 46 × 28 × 24 | 8 kg |
| Lufthansa | 55 × 40 × 23 | 8 kg |
| Delta | 43 × 33 × 19 | No strict limit |
| United | 43 × 28 × 23 | No strict limit |
| American Airlines | 48 × 32 × 22 | 9 kg |
| Turkish Airlines | 55 × 40 × 20 | 8 kg |
| KLM | 46 × 28 × 24 | 8 kg |
| Iberia | 45 × 35 × 25 | 8 kg |
| Swiss | 55 × 40 × 23 | 8 kg |
| British Airways | No cabin pets allowed | |
Height is the dimension that catches people most often. It's measured at the highest point of the carrier, including the handle. Some airlines tolerate +1–2 cm on soft-sided carriers that compress; others measure strictly. Don't gamble on this.
3. Soft-Sided vs. Hard-Sided Cabin Carriers
Soft-sided (recommended for most cabin travel):
- Flexible walls compress slightly to fit under tight seats
- Lighter (500 g to 1 kg), which matters when weight includes the carrier
- More comfortable for stressed pets (den-like feel)
- Folds flat for storage when not traveling
- Ventilation through mesh panels on 2–3 sides
- Best for: cats, small dogs under 7 kg
Hard-sided (cabin or cargo):
- Better protection for pets that scratch or bite at the walls
- Easier to clean after accidents
- Some airlines require hard-sided even in cabin (rare, but check)
- Heavier (1.5–3 kg), eats into your weight allowance
- Best for: anxious pets who might damage a soft carrier, or pets that need cargo
Recommended soft-sided models: Sherpa Original Deluxe, Sleepypod Air, Ibiyaya Collapsible. All fit most airline limits and run $60–$150.
Recommended hard-sided models: Petmate Sky Kennel (small), Vari Kennel (small). $40–$80 for cabin sizes.
4. IATA Cargo Crate Requirements
For cargo transport, your crate must meet IATA Live Animal Regulations (LAR). Airlines check these at the cargo terminal and will reject non-compliant crates on the spot.
Mandatory specs:
- Material: Rigid plastic or fiberglass. No wood, no wire-only, no collapsible.
- Fasteners: Metal bolts at all four top corners. Plastic clips alone are rejected by most airlines. Buy bolt kits separately if needed ($5–10).
- Ventilation: Mesh or grate openings on at least 3 sides. For international flights, 4 sides recommended.
- Door: Metal grate (not plastic), with a double-lock mechanism.
- Water bowl: Attached to the door, refillable from outside without opening the crate.
- Absorbent pad: On the floor of the crate.
- Labeling: "LIVE ANIMAL" stickers on all 4 sides and top, with arrows indicating which side is up. Your name, phone, flight number, and destination.
- No wheels: Or wheels must be removable (and removed before check-in).
Recommended cargo crate brands: Petmate Sky Kennel (all sizes), Vari Kennel (intermediate to giant), Ferplast Atlas Professional. All IATA-compliant out of the box.
5. IATA Crate Sizing Chart
The crate must be large enough for your pet to stand with ears up without touching the roof, turn around fully, and lie down stretched out.
| IATA Size | Dimensions (L×W×H cm) | Typical breeds |
|---|---|---|
| #100 (XS) | 48 × 32 × 26 | Cats, Chihuahuas, toy breeds |
| #200 (S) | 56 × 37 × 32 | Jack Russell, Dachshund, Pomeranian |
| #300 (M) | 71 × 52 × 49 | Beagle, Cocker Spaniel, Border Collie |
| #400 (L) | 92 × 66 × 62 | Labrador, Golden Retriever, Boxer |
| #500 (XL) | 102 × 74 × 72 | German Shepherd, Husky, Rottweiler |
| #700 (XXL) | 122 × 78 × 84 | Great Dane, Saint Bernard, Mastiff |
If your pet is between sizes, always go up. A crate that's too small will be rejected. A crate that's slightly too large is never a problem.
6. How to Measure Your Pet
Three measurements with a tape measure, pet standing naturally on all fours:
- Length (A): Tip of nose to base of tail (not the end of the tail).
- Height (B): Floor to top of head (ears up for dogs with erect ears, ears flat for floppy-eared dogs).
- Width (C): Widest point across the shoulders.
IATA minimum crate dimensions:
- Crate length = A + half the length of front legs
- Crate height = B + 5 cm clearance
- Crate width = C × 2
Example: A Labrador measuring 60 cm long, 55 cm tall, 30 cm wide needs a crate at least 75 × 60 × 60 cm. That's an IATA #400 (L).
For cabin carriers, measure differently: your pet needs to be able to lie down and turn around inside, but the carrier also has to fit the airline's under-seat dimensions. Measure both your pet AND the under-seat space on your aircraft if possible.
7. Crate Training: The Non-Negotiable Step
A pet in an unfamiliar crate at an airport is a stressed, panicking animal. A pet who's been crate trained sleeps through the flight. This is the single biggest factor in whether your pet has a good or bad travel experience.
4-week minimum timeline:
- Week 1: Crate open at home, treats inside, let them explore freely. No closing the door.
- Week 2: Feed meals inside the crate. Close the door for 5 minutes, then 15, then 30. Stay in the room.
- Week 3: Close the door for 1–2 hours. Leave the room. Short car rides with the crate.
- Week 4: 3–4 hour stretches. New environments. Simulate airport noise (play YouTube videos of airport sounds).
By flight day, your pet should walk into the crate on command and settle within minutes. If they're not there yet, postpone the flight if you can.
Never sedate instead of training. Every airline and veterinary association advises against sedation for air travel. It impairs breathing and temperature regulation at altitude. Natural calming aids (Adaptil for dogs, Feliway for cats, a worn t-shirt of yours) are safe alternatives.
8. Common Mistakes That Get You Rejected at Check-In
- Carrier too tall: The #1 rejection reason for cabin. Height is measured at the highest point including handles and zippers.
- Plastic clips only on cargo crate: Most airlines require metal bolts. Add them yourself if your crate only has clips.
- No water bowl on cargo crate: IATA mandatory. Must be attached to the door and refillable from outside.
- Wheels still attached: Many airlines require wheel removal for cargo crates. Choose a crate with detachable wheels.
- New crate, no training: First time in the crate = maximum stress = risk of injury, excessive barking, or airline removing you from the flight.
- Wrong weight: Weigh your pet IN the carrier on a home scale. Airlines weigh at the counter and won't negotiate.
- Missing labels: Cargo crates need "LIVE ANIMAL" stickers with arrows on all sides. No stickers = delay at the cargo terminal.
- Leash attached outside: Nothing should hang from the outside of the crate. Leashes, collars, and harnesses go inside or in your bag.
9. Frequently Asked Questions
Can I use a backpack carrier for cabin?
A few airlines accept ventilated pet backpacks (Sherpa, Sleepypod Go) but most don't. Check before you buy. Standard soft-sided carriers are the safe choice.
Can two pets share one crate?
IATA allows it for animals from the same litter under 6 months old with similar weight, or for two cats that live together. Beyond that, one pet per crate.
How much does a good carrier cost?
Soft-sided cabin: $60–$150. Hard-sided cargo IATA: $80–$300 depending on size. The bolt kit for cargo crates is an extra $5–10.
Should I put food in the crate?
For flights under 8 hours, no. Water yes (frozen bowl to prevent spills). For flights over 8 hours with a layover, attach a small food bowl with dry kibble.
Can I open the carrier during the flight?
No. Every airline prohibits opening the carrier during any phase of flight. You can talk to your pet through the mesh but the zipper stays closed.
What if my carrier is rejected at the gate?
Some major airports (CDG, FRA, LHR, JFK) sell emergency carriers near the check-in area. But don't count on it. Arrive 3 hours early for international flights so you have time to solve problems.
Do I need a different carrier for the return trip?
No, same carrier works both ways. Just make sure it still meets the requirements of your return airline if you're flying a different carrier back.
10. Get Your Carrier Checked Before You Fly
Every airline has different dimensions, and your pet's size determines whether you need cabin or cargo. Instead of cross-referencing airline PDFs, use PawGo to check your pet's size against your airline's exact carrier limits in 30 seconds. It flags dimension issues before you buy.
Related guides: How to fly with a dog · Flying with a cat · Snub-nosed breed guide · Cost breakdown · Best airlines for pets