In the aviation industry, standby duty (often called "Airport Reserve") refers to a specific shift where flight crew members, such as pilots and flight attendants, are required to be physically present at the airport, in full uniform and ready to fly at a moment's notice. This duty exists to ensure operational reliability; if a scheduled crew member is late, falls ill, or exceeds their legal "duty hours" due to weather delays, the standby crew is immediately "activated" to take their place. In 2026, standby shifts are strictly regulated by aviation authorities to manage fatigue. A crew member on airport standby typically waits in a dedicated "crew lounge" for a block of 4 to 8 hours. If they are not called for a flight by the end of their shift, they go home, but if they are called, they must be able to reach the aircraft and begin pre-flight checks within 15 to 30 minutes. This role is the "insurance policy" of the airline, preventing thousands of flight cancellations daily.