Many pet owners choose crates based on weight because that's how they're marketed in stores ("for pets up to 20 lbs."). But for air travel, weight-based sizing is inaccurate and unsafe. IATA LAR CR#1 requires sizing based solely on the pet's dimensions — height, length, and width — not pounds.
Here are the four reasons why:
1. Weight Does Not Reflect Body Shape
Pets of the same weight can have completely different proportions.
A 20-lb French Bulldog, 20-lb Whippet, and 20-lb Maine Coon all have very different heights and lengths. Weight alone tells you nothing about how much space the animal needs to stand, turn, or lie comfortably.
2. Breed Variation Makes Weight Almost Useless
Long-bodied, short-legged breeds (Dachshunds, Corgis), tall slender breeds (Whippets, Greyhounds), broad-chested breeds (Bulldogs), and even different cat breeds all vary dramatically in posture and structure. A weight-focused crate will be too small for many of them.
3. Incorrect Height Clearance Creates Real Welfare Risks
If a pet cannot stand naturally without touching the top of the crate, it can't maintain proper posture, ventilation, or comfort. Poor clearance leads to stress, restricted movement, and increased risk of respiratory issues—especially on long flights.
4. CR#1 Uses Dimensions Because Dimensions Protect the Animal
CR#1 sizing uses simple anatomical measurements (length, height, and width) to ensure the crate fits the actual pet—not a marketing category. This protects posture, mobility, and safety during turbulence and handling.
Bottom Line
Weight does not determine crate size.
Anatomy does.
For safe, compliant air travel, always size the crate based on your pet's dimensions—not the number on the scale.
When Pets Fly® — All Rights Reserved.
This article contains original educational material created by Dr. Nelva J. Bryant for the purpose of promoting safe, welfare-focused air travel for pets. No part of this article—text, images, or graphics—may be copied, reproduced, distributed, or adapted without written permission from When Pets Fly®. 11/23/2025