From the way that every airline makes an effort to have a duty free catalog, even
UA has one, it means that duty free generates additional revenues for the airlines.
On Asian airlines, such as Asiana, China, EVA, Cathay Pacific, they make sure that they sell duty free twice on the long haul flight... one after dinner and one after breakfast. They served breakfast like 2 and 1/2 hours prior to arrival... just to make times for last minute duty free shoppings. On the
HKG-
TPE flights, (only an hour), the airline will still assign to one or two F/As just to sell duty free products...
I don't smoke, but always buy Marlboro cigarettes for friends and families... Sometimes they run out of popular brand of cigarettes in
CX, even when I fly business...
I remember when EU bans duty free on EU internal flights, it creates an uproar among European airlines... that explains that duty free has a value. Free meals may be gone, but duty free will always be there.
Carfield