Since airlines operate day and night, year-round, flight attendants must have a flexible schedule. Generally, they work no more than 12 hours per day, but may in some cases - especially in the event of oversea international flights - work 14 hours or more. Attendants also work on holidays and weekends and typically fly for 65 to 90 hours per month, with another 50 hours spent on the ground preparing or waiting for flights.