Slumping, sighing or grimacing when hearing this information will only hurt your chances of being hired. Recruiters watch for this kind of response when presenting the information, as it reflects the degree of your flexibility. A flight attendant's job requires so much flexibility with the constantly changing schedules and flight times, that this is a major concern of airline managers. If you cannot display a positive attitude in the face of adversity, this is probably not the job for you. Courtesy and friendliness also weigh heavily on a recruiter's decision.
Dependability is a big issue with recruiters as well.
They won't wait for you in a job open house. Doors close promptly at the designated time. It takes a lot of maturity and stamina to do this job. Enthusiasm and energy. Energy is contagious and interviewers love it.