Plain English Meaning

Flew the airplane alone for the first time (or on a later solo flight), with no instructor sitting next to them, after the instructor signed them off as ready.

Full Definition

Past tense of solo: to have flown an aircraft alone, without an instructor or other crewmember on board, after being authorized to do so by a flight instructor. A student pilot's first solo flight is a recognized milestone in flight training and is endorsed in the student's logbook by the instructor.

Context Anchor

Used when discussing a student's training progress, especially the point when the student first flies without the instructor on board.

Derivation

From the Italian 'solo' meaning 'alone,' originally a musical term for a passage performed by a single performer. In aviation it carries the same idea: the student is now performing the alone.