What documents must a pilot carry when flying?

The correct answer emphasizes the essential documents that a pilot must carry while flying to comply with regulations. The pilot certificate is a legal proof of a pilot's qualification to operate an aircraft. The medical certificate indicates that the pilot has passed a medical examination and is deemed physically fit to fly. A government-issued photo ID serves as identification, confirming the pilot's identity in conjunction with the other documents.

Together, these documents ensure that the pilot meets legal requirements and is adequately qualified and authorized to operate an aircraft. This combination is critical for safety and regulatory compliance during flight operations. Other options listed do not meet the mandated documentation requirements set forth by aviation authorities.