An American Airlines flight attendant needed five stitches after an emotional support dog bit him on the hand, the airline says. American did not disclose what kind of dog was involved in the incident Monday on a flight from Dallas to North Carolina, USA Today reports. The flight attendant's union called for the Department of Transportation to bring in standards for certifying emotional support animals. "What happened on yesterday’s American Airlines flight is completely unacceptable and inexcusable,'' the Association of Flight Attendants-CWA said in a statement Tuesday. Trainers say owners of emotional support animals need to make sure they are ready to fly. "We need to make sure, as part of our caretaking for them, that we're not putting them in situations that they're not ready for and unprepared for," Kat Carver, a trainer at Saving Grace K9s, tells Fox 8. (More emotional support animal stories.)