Keeping a cat in a sealed cardboard box for an extended period can cause it to suffocate. Generally, it's recommended that owners make several holes in the box, drilling holes on all four sides, to allow the cat to breathe. During transport, owners should also check on the cat frequently inside the box.
Air freight is the most common way to transport cats, and it's also the least impactful, fastest, and least harmful method. Of course, it's also the most expensive and has the strictest requirements. However, for long-distance transport, air freight is the best and only option.
