Glossary
What is a pilot certificate?
The document the FAA issues showing what kind of flying a person is qualified to do, from student pilot up to airline transport pilot. Americans say license in conversation, but certificate is the word the regulations use, and the document itself carries no expiry date.
Also called Pilot license
That is the whole entry for now. The longer version, with the mechanics and worked examples, is still to be written. See autorotation for how those read once they exist.