Applicability

This regulation introduces the section of Part 121 that covers route approval requirements. It applies specifically to certificate holders (airlines) conducting domestic or flag operations—meaning scheduled airline operations within the United States or between the U.S. and foreign countries.

In practical terms, this tells you that airlines can't simply decide to fly wherever they want. Before operating on any route, they must obtain FAA approval demonstrating they can safely conduct operations along that specific route. This includes proving adequate navigation facilities exist, suitable airports are available for normal and emergency operations, and the airline has appropriate operational procedures in place.

The regulation sets the scope for the detailed route approval requirements that follow in this subpart. If you're studying Part 121 operations, understanding that route approval is mandatory—not optional—is fundamental to how airlines plan and certificate new service.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*