From the Alaska Airline page
Fee Summary
Pet in Cabin $100.00 (USD) each way
Pet in Baggage $100.00 (USD) each way
The following regulations apply:
•Dogs and cats must be at least eight (

weeks of age and weaned.
•No more than one (1) live dog or cat, 6 months of age or older, may be transported in the same kennel.
•No more than one (1) live puppy, 8 weeks to 6 months of age, and weighing over 20 lbs, may be transported in the same kennel.
•No more than two (2) live puppies or kittens, 8 weeks to 6 months of age, that are of comparable size, and weighing 20 lbs or less each, may be transported in the same kennel.
Animals must be harmless, inoffensive (not destructive to itself or the kennel), and require no attention during transit.
The health of your pet is important. Due to health risks that could potentially result in the death of the animal, brachycephalic (shortnose) dogs/cats are only accepted for travel at owner's risk and excess valuation is not available. The following is a list of the affected breeds:
Dogs: American Pit Bull, American Staffordshire, Boston Terrier, Brussels Griffin, Bull Mastiff, Bull Terrier, Chow Chow, Dutch Pug, English Bulldog, English Toy Spaniel, French Bulldog, Japanese Boxer, Japanese Spaniel, Pekinese Pug, Shih Tzu, Staffordshire Bull Terrier, Terrier, Bulldog, Pug, Boxer.
Cats: Burmese, Exotic, Himalayan, Persian.
The USDA and IATA have specific requirements (PDF 289k) for kennels traveling in the cargo compartment.
Alaska Airlines is committed to the health and safety of your pet during travel. To ensure your pet travels safely, checked kennels must meet the following requirements, in addition to USDA/IATA requirements:
Kennel Must:
Kennel Must Not:
Be of solid construction and composed of plastic, wood, metal or material of comparable strength and able to withstand rigors of normal transportation.
Be collapsible, snap-top or soft-sided, or composed of wire, mesh, cardboard or wicker.
Be secured with nut and bolt type fasteners if the kennel is not constructed as one piece. View example
Be secured with twist, slide, snap or zip tie fasteners. View example
Be escape-proof with a metal grated door fastened securely to prevent accidental opening.
Have a plastic door.
Be constructed with original or standard replacement parts.
Be secured using zip ties, duct tape or rubber bands.
Have handles or handholds on the exterior to lift without tipping.
Have permanently attached wheels. Wheels must be removed or rendered inoperable.
Have a solid roof. Ventilation slots are permitted if roof integrity remains intact.
Have sharp points or edges, with no protrusions that could injure the animal.
Have adequate air ventilation. Vents must be covered with permanent bars or other sturdy material.
Be secured with a lock.
Be clean and leak-proof with absorbent bedding made of material that is safe and non-toxic to the animal.
Contain bedding material when traveling to Mexico. Shredded paper or absorbent pads are acceptable.
Contain a food and water dish clipped inside the door to allow feeding without opening the door.
Allow the animal to stand up (head erect and not touching the top), lie down and turn around in a normal, comfortable position.
The Following Kennel Sizes are Allowed on Alaska Airlines:
Size
Kennel Size
Dimensions (height x width x depth)
Extra Small
100
15" x 16" x 21"
Small
200
19" x 20" x 27"
Medium
300
23" x 22" x 32"
Large
400
26" X 24" x 36"
Extra Large*
500
30" x 27" x 40"