If a service animal/emotional support animal is too large to fly in cabin, then the airline may fly the animal in a carrier with the baggage for free. The dog is supposed to fit at the handler’s feet and not encroach on another’s person’s space or into the aisle.

We fly with my husband’s guide dog for the blind. She weighs 60 pounds and I think, as does Guide Dogs for the Blind, that a dog should not be any bigger if you are going to fly a lot. It’s for the dog’s comfort and consideration for others. My husband’s dog can curl up but on long flights she will encroach on my space which is okay. My husband takes the window seat and I take the middle so we don’t bother the person in the aisle seat. The dog has been on 200 flights and several flights to Europe. For that sheepdog to lop over in the aisle is a safety hazard and the attendant should have said something. We see many people taking advantage of the rules about flying a dog in cabin and the disabled with true service dogs are hurt by the thoughtlessness of the offenders.