There are no laws dictating the type of carrier to use, but remember that it must be small enough to fit under a standard airplane seat and should generally not exceed 45 linear inches (length + width + height), or roughly 21.5 by 15.5 by 9 inches. Depending on the airline, carrier size limits may be even smaller.
How do you measure a pet for an airline carrier?
MEASURE YOUR PUP'S LENGTH & WIDTHIf you have a measuring tape handy, you can also take their measurements to confirm it will be a good fit. Start at the front of their chest and measure the distance to their rear. For their height, measure from the top of their shoulder blade to the base of their paw.
How do you fly with a 30 pound dog?
So long as your dog is crated, many airlines, such as Alaskan or American Airlines, allow large dogs to be checked baggage. As the pet owner, you will bring your dog to check in as you would normally with your other bags, and then they will be weighed and moved like the rest of your bags.