For in-cabin pets, Alaska Airlines requires a carrier that fits completely under the seat in front of you. As a general guide, Alaska’s published maximum for an in-cabin pet carrier is typically up to 17” L x 11” W x 9.5” H for a soft-sided carrier—though exact under-seat space can vary by aircraft and seat location.
The safest approach is to choose a carrier that’s slightly under the maximum and has flexible sides, so it can gently compress to slide under the seat without stressing your pet. Your dog (or cat) should be able to stand up, turn around, and lie down comfortably inside the carrier.
Along with sizing, Alaska Airlines expects the carrier to be secure and travel-ready: ventilated, leak-resistant, and designed to keep your pet safely contained. Many travelers prefer soft-sided carriers with sturdy zippers, reinforced seams, and a supportive base—comfort matters when your pup is settling in for takeoff, taxi, and landing.
Measure your dog from nose to base of tail and from floor to top of shoulders, then compare those numbers to the carrier’s interior space (not just the exterior). If your dog is between sizes, prioritize a roomier interior that still fits under-seat. Also consider bringing a thin, washable mat or blanket for cozy support without stealing precious headroom.
If you’re building a more comfortable travel setup—carrier, padding, organization, and on-the-go essentials—this guide can help: https://kingwuff.com/blog/guide-pet-travel-comfort-gear-dog-carriers-walk-bags-tips/.
They can be strict if the carrier won’t fit under the seat or doesn’t fully enclose your pet. A soft-sided carrier close to the maximum size is often easiest to fit, but it still must slide under the seat.
There’s no single “dog size” rule—your dog must be able to stand, turn, and lie down inside a carrier that fits under the seat. In practice, small dogs that fit comfortably in an under-seat carrier are the best candidates for in-cabin travel.
Schedule an exam with a licensed veterinarian, who can issue the required paperwork if your dog is healthy and up to date on vaccinations. Timing matters, so confirm the destination and airline requirements before your appointment.
