If restricted by flight regulations, we recommend that readers be powered off during a flight and not used for scanning a Sensor. Aviation regulations dictate that a flight crew may decide that they do not want any electronic devices powered on during a flight regardless of device. In general, the FreeStyle Libre system is not restricted by flight regulations and can be used since it meets the RTCA guidance of use of medical devices on planes.  The strip port on the reader can be used to take blood glucose or ketone readings during flight.  Turning on the reader with the Home Button will activate the radio.  Users must turn on the reader by inserting a test strip to avoid activating the radio.¹

Reference

1. FreeStyle Libre flash glucose monitoring system User's Manual.