Flight Operations
Part 91 - General Operating Rules
Basic rules for operating an aircraft within the United States
Part 121 - Commercial Operations
Rules for scheduled air carriers and operations
Part 135 - Commuter and Charter Flights
Rules for commuter and on-demand operations
Licensing & Certification
Part 61 - Pilot Certification
Requirements for pilot certification and ratings
Part 67 - Medical Standards
Medical certification requirements for pilots
Part 141 - Flight Schools
Requirements for certified flight schools
Aircraft Requirements
Part 21 - Certification Procedures
Aircraft certification and airworthiness requirements
Part 43 - Maintenance
Maintenance, preventive maintenance, and alterations
Part 45 - Identification
Aircraft registration and marking requirements
Safety & Security
Part 107 - Drone Operations
Rules for commercial drone operations
Part 139 - Airport Certification
Requirements for airports serving commercial aircraft
Part 1544 - Aircraft Security
Security requirements for aircraft operators