What is an example of a sign that a passenger might be intoxicated?

The presence of the smell of alcohol is a clear indicator that a passenger may be intoxicated. This is often one of the most noticeable signs, as it directly signifies that the individual has likely consumed alcoholic beverages. Flight attendants are trained to identify this characteristic, as it can be essential for ensuring the safety and comfort of all passengers onboard.

Calmness, reading quietly, and being friendly do not inherently suggest intoxication. These behaviors can be exhibited by sober individuals as well and do not provide a reliable indication of someone's level of alcohol consumption. Identifying the smell of alcohol is a more definitive and immediate sign that can prompt further assessment or action by the flight attendants.