What is the purpose of the Airport Transportation System (ATS)?

The Airport Transportation System (ATS) serves the critical function of connecting various terminals and parking areas at airports, such as O'Hare. This system is designed to efficiently move passengers and their luggage across the airport premises, ensuring that travelers can easily access different terminals and locations. By providing this connectivity, the ATS enhances the overall passenger experience, allowing for smoother transitions between flights, gates, and parking facilities.

The other options, while related to transportation, do not encapsulate the primary purpose of the ATS. For instance, shuttle services specifically designed for passengers might be a feature of the broader transit system but do not specifically highlight the terminal connectivity function. Transporting cargo is a separate operational task that utilizes different systems tailored for freight, while public transportation to the airport typically involves city buses or trains that are not part of the ATS framework. Thus, the correct answer highlights the ATS's essential role in enabling seamless movement within the airport complex.