Certain air carrier airports certified under FAR Part 139 are required to submit an implementation plan for a safety management system (SMS) on the following deadlines: April 24, 2024, for airports designated as hubs; Oct. 24, 2024, for airports with 100,000 or more annual operations over the previous three years; and April 25, 2025, for airports classified as port of entry, landing rights, user fee, and international facilities