These are physical vouchers previously distributed by a particular air carrier, entitling the holder to a complimentary alcoholic beverage during a flight. For instance, a passenger might receive one of these upon experiencing a significant delay or as a gesture of goodwill from a flight attendant.
These provided a tangible benefit to travelers, enhancing the onboard experience and representing a form of compensation for inconveniences. Historically, they were a common tool used by airlines to improve customer satisfaction and foster positive relationships with their passengers.