Yes, airlines reserve the right to deny boarding to passengers who appear to be excessively intoxicated or disruptive.

Yes, you can absolutely be denied boarding if you appear to be intoxicated, and this is a strictly enforced safety regulation worldwide. Under FAA regulations in the United States (and similar EASA or CAA rules abroad), airlines are legally prohibited from boarding any passenger who "appears to be intoxicated." The gate agents and flight attendants are trained to look for signs such as slurred speech, unsteady gait, aggressive behavior, or the strong smell of alcohol. The primary reason is safety: an intoxicated passenger may be unable to follow emergency instructions, could become a disruption to others, or might face medical complications at high altitudes where the effects of alcohol are often intensified. If you are denied boarding for intoxication, the airline is generally not required to provide compensation or a free rebooking, as the situation is considered a violation of the contract of carriage. In many cases, you will be required to wait until the next available flight once you have sobered up, and you may be subject to additional security screening or even law enforcement intervention if your behavior was disruptive during the denial.