If you plan to take your assistance dog with you on the flight, it is essential that you tell the airline about this in advance.
Airlines must accept all assistance dogs for air travel without charge.
Dogs will normally sit in the space on the floor in front of the seat (many airlines will seat passengers with guide dogs in the front row, if possible, where there is usually a little more space).
If it is not possible for the dog to sit there or the dog is of a larger breed, then an airline may charge for a second seat in order for there to be enough floor space for the dog to lie down.
A safety harness should be taken on the plane to enable your dog to be secured during take-off and landing.
An airline may ask for confirmation that your dog has been trained to a standard that allows it to travel safely by air.