: a person who attends passengers on an airplane
About the Word
The question isn't "when did the title of stewardess change to flight attendant?" but "when did the title of flight attendant change to stewardess," since the evidence we have suggests that flight attendant was in use first.
Although stewardess has been used since at least 1631 to refer to ‘a woman who performs the duties of a steward’, our earliest example of it being used specifically in relation to a woman in an aviation setting comes from 1931. Flight attendant, however, has been used since at least 1928 (a headline in The Christian Science Monitor from October 27th of that year reads ‘Flight Attendants Raise Title Issue’). The article says that “what to call the attendant who takes care of the passengers in the big air liners is a problem perplexing the transport companies,” and notes that at least one of the flight attendants in question “was recently offended by a passenger calling him the ‘cabin steward.’”
“It’s best to avoid masculine or feminine terms and expressions and to substitute more gender-sensitive words. For example, instead of ‘policeman’ or ‘policewoman,’ say ‘police officer;’ instead of ‘stewardess,’ say ‘flight attendant.’” —Cheryl Hamilton, Essentials of Public Speaking, 2011