Flight attendants, formerly called sky girls, air hostesses, stewardesses and stewards hold the primary responsibility for the safety and comfort of airline passengers. The role is based on similar jobs on passenger ships, but has more direct involvement because of the confined quarters and shorter travel times on airplanes. Flight attendants in their collectivity form a cabin crew.

The first flight attendant was Ellen Church. Hired by United Airlines in 1930, she also first envisioned nurses on airplanes. Other airliners followed suit, hiring nurses to serve as stewardesses on most of their flights. The requirement to be a registered nurse was relaxed at the start of World War II, as so many nurses enlisted into the armed services.

The primary responsibility of the flight attendant's job is the safety of the passengers, but most of the work is customer service, serving meals and drinks and accommodating the individual needs of passengers. These roles sometimes conflict, as when flight attendants must cut off drinks for a passenger who has had too much, or to force passengers to fasten seat belts, sit down, or otherwise follow safe procedures.

Particularly in the 1960s and 1970s, the airlines contributed to confusion about these roles by advertising the attractiveness and friendliness of their "stewardesses." One airline used named pictures stewardesses with captions like "I'm Kristin. Fly me." Another airline, Braniff Airways, had the stewardesses changing clothes during the flight, wearing one garment while greeting passengers and another for serving meals. In advertisements, this practice was called the "air strip," and was advertised with suggestive music. A policy of at least one airline required that only unmarried women could be flight attendants.

The 1967 book Coffee, Tea, or Me?: The Uninhibited Memoirs of Two Airline Stewardesses "by Trudy Baker and Rachel Jones" emphasized this aspect of the role. In fact, given the relative affluence of airline passengers and the presence of attractive young women, many marriages and other relationships undoubtedly began on planes. The story in Coffee, Tea, or Me? was recently revealed to be a fabrication; its supposed authors are ficticious. It remains a good depiction of the "sexy stewardess" stereotype.

On the other hand, in the 1980s, The Replacements sang a song called "Waitress in the Sky" about the drearier aspects of the work.

Airlines were accustomed to firing female flight attendants, even after years of service, if they were deemed too old or unattractive, but a decision by the National Labor Relations Board, in the United States, ended that practice and recognized the professionalism of the job. By the end of the 1970s, airlines called the former stewardesses "flight attendants".

The role of flight attendants received heightened prominence after the September 11, 2001 attacks when flight attendants (such as Sandra W. Bradshaw and Madeline Amy Sweeney) actively attempted to protect passengers from assault and also provided vital information to air traffic controllers on the hijackings. In the aftermath of the attacks, flight attendants were given heightened responsibilities for the security of their planes.

Flight attendant training is usually done in a hub city of the airline and lasts about six weeks, covering both safety and comfort. Flight attendants have to be at least 19 and often have to be able to speak a foreign language.