Prior to the Transport Department ruling airlines had to rule on which animals qualified as comfort or emotional-support aides, and make decisions on a case-by-case basis.
This previously led to many arbitrary rulings with some airlines allowing exotic animals such as mini-service ponies, while others refused board to passengers trying to bring squirrels, turkeys or peacocks.
The Department finally gives some precedent and relief to airlines having to lay the ground rules on flying with comfort pets.
Air Alaska, which was one of the first US airlines to move on the new Support Animals, said they had " numerous instances of emotional support animal misbehaviour which caused injuries, health hazards and damage to aircraft cabins."
Southwest is the last of the nation's six largest airlines to change its animal policy after the Transportation Department action.
International airlines flying to the States also have to contend with legal requirements concerning support animals.
Air New Zealand currently has rulings on where psychiatric service dogs "may be permitted to travel in the aircraft cabin for travel to and from the USA (but not other routes)".
However, this is dependent on 48 hours notice and the animal having proof of relevant training and behaviour - in line with the definitions in the US Air Carrier Access Act.
Emotional support dogs, therapy dogs or comfort dogs are all not allowed inside the cabin for travel.
- AP with additonal reporting