Yes, airlines maintain a system known as "Reserve" or "Standby Duty" to ensure that flights can depart on time even if a scheduled crew member calls in sick, gets stuck in traffic, or is delayed on a connecting flight. Flight attendants on reserve are divided into two main categories: Airport Standby and Home Standby. Those on Airport Standby are in full uniform at the airport, ready to board a plane within 15 to 30 minutes of being called. Those on Home Standby must stay within a specific radius of the airport (usually 90 minutes or less) and be ready to report for duty as soon as they receive a phone call. Being on reserve is often a requirement for junior flight attendants and can be quite stressful, as they do not know where they are going or for how long—they might be called for a 1-hour "turn" to a nearby city or a 5-day international trip to a different continent.