The Japan Airlines pet policy is as follows:
Pets are not accepted in the cabin.
Pets will travel as cargo on domestic flights and be handled by our subsidiary company, JAL Cargo.
Dogs, cats, small birds (that eat seeds, fruit and insects), rabbits, ferrets, hamsters, marmots, squirrels, chinchillas are allowed for transport.
French Bulldogs and Bulldogs cannot be checked. These breeds are no longer accepted on any flight due to their relative susceptibility to suffering health issues as a result of the aircraft cargo environment.
JAL offers different handling procedure for international and domestic flights to ensure the safety and comfort for animal transport.
For passengers who wish to travel with pets on the same flight, the pets are checked-in as checked baggage. In that case, the handling defers from cargo.
Taking a pet to a foreign country involves preparation and planning far in advance of your departure date. Requirements for pet travel to a foreign country are set by the destination country. If you are you traveling to another country and bringing along your pet you’ll need to meet the animal health requirements of the country you are visiting.
More information on the Japan Airlines pet policy