What is the main function of flight progress strips?

The main function of flight progress strips is to post current data on air traffic, which serves as a vital tool in air traffic control. These strips provide a clear, concise representation of the status and progress of individual flights. Each strip contains essential information, such as the aircraft's identity, position, altitude, flight plan details, and estimated times.

By presenting this information in a visually accessible format, air traffic controllers can efficiently monitor and manage multiple aircraft in their airspace. The use of flight progress strips aids in maintaining situational awareness, allowing controllers to make informed decisions regarding separation, sequencing, and coordination between aircraft. This system is particularly useful in busy control environments, ensuring that all relevant information is readily available at a glance, thereby enhancing overall operational safety and efficiency.

The other choices focus on aspects such as clearances or aircraft service records, which are not the primary purpose of flight progress strips. While these elements are indeed important in air traffic operations, they do not reflect the primary role that flight progress strips play in delivering real-time data on active flights.