What documents must a pilot have in possession while operating as pilot in command of an aircraft?

A pilot must have an appropriate pilot certificate and a current medical certificate in their possession while acting as pilot in command of an aircraft. The pilot certificate verifies the pilot's qualifications to operate the specific type of aircraft being flown, including endorsements for specific aircraft categories, classes, or types. The medical certificate demonstrates that the pilot meets the necessary health standards required to safely operate an aircraft. Both documents are crucial as they ensure that the pilot is legally authorized and medically fit to fly, which aligns with regulatory requirements set forth by aviation authorities.

Other options may involve important documents for flight operations but do not fulfill the specific legal requirement for documentation when acting as pilot in command. For instance, a flight plan and weather briefing are useful for flight safety and planning but are not mandatory documents that must be carried by the pilot. Similarly, proof of insurance and aircraft registration are important for legal operation of the aircraft but do not pertain directly to the pilot's qualifications. A logbook and personal identification can be relevant for various purposes, but again, they do not satisfy the core requirement for certification and medical verification needed while flying.