What information is typically circled in red on flight plans?

The information typically circled in red on flight plans is used to indicate important updates or revised information that is crucial for the operational awareness of all parties involved. This signaling is critical for ensuring that any changes, such as revised routes, altitudes, or other essential data, are easily identifiable at a glance. By using red ink, controllers and pilots can quickly draw attention to significant updates that may affect the flight's execution and safety.

This practice of highlighting crucial information in red is standard in aviation communication to minimize the risk of misinterpretation or missed updates, thereby enhancing overall flight safety and efficiency.