The airlines make their own rules, each airline has different rules. The ADA had to tighten their rules because of some of the crazy things that people do on airlines such as bringing exotic animals on the planes. Other people have brought in full-size horses into grocery stores. RS 6 foot long snake into a restaurant. These people with their poor judgment caused the rules to be tightened by the ADA. Some people just don't have common sense and the rest of us pay for it, with stupid rules and confusing guidelines.