What tool does a flight instructor provide to certify student pilot solo readiness?

A flight instructor certifies a student pilot's solo readiness by providing an endorsement. This endorsement is a formal acknowledgment that the instructor has evaluated the student’s flying skills and has determined that they are sufficiently proficient and knowledgeable to fly solo.

The endorsement typically includes specific information such as the student's name, the make and model of the aircraft that the student is authorized to fly solo, and the date of the endorsement. This document serves as proof that the student has met the necessary training requirements and has received the instructor's approval to conduct solo flight operations in accordance with FAA regulations.

The other options, while relevant to flight training, do not fulfill the specific function of certifying solo readiness. A solo logbook is primarily used by students to log their solo flights, an operational checklist is a tool used to ensure all pre-flight and operational steps are followed during flight, and a training syllabus outlines the training plan and objectives but does not constitute a certification by the instructor.