Yes, solo flight time is considered Pilot-in-Command (PIC) time under both FAA and EASA regulations, but the context varies by license level. For student pilots, FAR 61.51(e)(4) explicitly states that a student pilot may log PIC time when they are the sole occupant of the aircraft while training for a certificate and have a current solo endorsement. For certified pilots, solo time is a subset of PIC time because they are the "sole manipulator of the controls" for an aircraft for which they are rated. In fact, most regulatory bodies require a specific amount of "Solo PIC" time for advanced ratings, such as the 10 hours required for a Commercial Pilot Certificate. It is important to note that while all solo time is PIC time, not all PIC time is solo; for example, a pilot can log PIC time while flying with passengers or an instructor, provided they are the legal Pilot-in-Command or the sole manipulator of the controls in a rated category.