Flight attendants work for particular airlines, and make sure that all the passengers are safe and comfortable during air travel. Air hostess is a term used for female flight attendants, but it is not a very common term at present. Instead, flight attendant is the more commonly used job description. 

Cabin Crew is an umbrella term that is used for all the people responsible for providing customer and safety support to passengers during air travel. Other than flight attendants, the purser and inflight chefs are also part of the cabin crew.