American Airlines is banning hoofed, horned, creepy and crawly creatures from flying as emotional support animals. Critters displaying threatening behavior such as growling or biting won’t be allowed on board, either.The carrier also will require 48-hour advance notice of plans to fly with an emotional or psychiatric support animal. Travelers will need to present a form signed by a mental health professional showing the disability involved, according to a post Monday on the Fort Worth, Texas-based airline’s website.