Why are some breeds restricted from flying?

Short-nosed (brachycephalic) breeds such as pugs, French bulldogs, English bulldogs, boxers, Persians, and Himalayans are restricted by many airlines because their shortened airways make them more vulnerable to breathing difficulties under heat and stress. Some airlines refuse them entirely; others impose seasonal embargoes, larger crate sizes, or specific routing rules. Your Airpets consultant will tell you immediately whether your breed has restrictions on your route.