Airline size reference
Airline Pet Carrier Size Limits: the Under-Seat Chart
Every major North American airline publishes its own maximum size for soft-sided in-cabin pet carriers. This chart collects those published numbers in one place (verified June 2026), with a detail page per airline. Sizes are a shopping reference, not an approval — under-seat space varies by aircraft, and the airline's current policy always has the final word.
| Airline | Published soft-carrier size (L×W×H in) | Metric (cm) | Detail |
|---|---|---|---|
| Delta | 18 × 11 × 11 | 45.7 × 27.9 × 27.9 | Delta details |
| United | 18 × 11 × 11 | 45.7 × 27.9 × 27.9 | United details |
| American | 18 × 11 × 11 | 45.7 × 27.9 × 27.9 | American details |
| Southwest | 18.5 × 13.5 × 8.5 | 47.0 × 34.3 × 21.6 | Southwest details |
| Alaska | 17 × 11 × 9.5 | 43.2 × 27.9 × 24.1 | Alaska details |
| JetBlue | 17 × 12.5 × 8.5 | 43.2 × 31.8 × 21.6 | JetBlue details |
| Frontier | 18 × 14 × 11 | 45.7 × 35.6 × 27.9 | Frontier details |
| Spirit | 18 × 14 × 9 | 45.7 × 35.6 × 22.9 | Spirit details |
| Hawaiian | 17 × 11 × 9.5 | 43.2 × 27.9 × 24.1 | Hawaiian details |
| Air Canada | 21.5 × 15.5 × 10.5 | 54.6 × 39.4 × 26.7 | Air Canada details |
| WestJet | 16 × 10 × 8.5 | 40.6 × 25.4 × 21.6 | WestJet details |
Reference values only, drawn from each airline's published pet policy. Policies change without notice — always reconfirm with your airline before booking travel.
How to use this chart
- Find your airline and note the smallest of its three dimensions — usually height is the tight one.
- Compare a carrier's listed dimensions against all three numbers, not just length. Our carrier fit guide shows how to measure your pet first.
- Soft-sided carriers compress a little; rigid carriers do not. Each airline detail page shows how TuckTrail's flight carriers compare, dimension by dimension.
- Before booking, open the airline's own policy page for fees, per-cabin pet caps, and route restrictions — each detail page links directly to the official source.
Flying soon? Start with our flight-ready carriers or the airline compliance overview for how we source and verify these numbers.
