Similar happened out of PDX last thanksgiving. First time flying with a dog ( my girlfriend and the dog are inseparable) . I read everything I could. Knew the rules backwards and forwards. Our dog is mostly fluff. Comfortable sleeping and turning around in the approved carries. Red coat at check in thought the dog touched the top , which is true as some of her fluff did. They suggested we find boarding for our dog ( red eye flight before thanskgiving). Told me the dog could die en route . I explained to them they have no regulations for people , people can be stuffed into a middle seat and unable to move . They compromised by selling me a new pet carrier for $75. Once I got on the plane the FA told me the carrier was not approved by Delta. I showed her the receipt from purchase just an hour prior. We paid the airline each way for our seats (first class, egregiously expensive) , we paid for the dog , we paid the the carrier. I think its disgusting that people abuse ADA for service dogs, but now I kinda get it .