Final answer:
The Airport Authority is responsible for operating an airport and managing access to restricted areas, setting the framework for other security-related entities.
Step-by-step explanation:
When it comes to operating an airport and specifically designating, protecting, and controlling access to restricted areas, the Airport Authority performs these functions. This organization is responsible for the overall management of the airport's infrastructure, including terminals that facilitate the efficient boarding of airplanes and the handling of luggage. While other entities like Airport Security Officers, Transportation Security Officers (TSO), and Customs and Border Protection (CBP) play significant roles in an airport's security and customs process, it is the Airport Authority that generally oversees and sets the framework for these operations.