Which airport does not have an Object-Free Area around its concourse buildings?

O'Hare International Airport does not have an Object-Free Area (OFA) around its concourse buildings primarily due to its historic design and specific layout determined by its location and the surrounding infrastructure. The Object-Free Area is a safety zone that must be free of obstacles to ensure the safe operation of aircraft during takeoff, landing, and taxiing. Airfields with high activity and intricate traffic patterns, like O'Hare, may have design constraints that limit the availability of space for an OFA.

In contrast, the other airports listed, such as Los Angeles International, John F. Kennedy International, and Dallas/Fort Worth International, have been designed or retrofitted with specified Object-Free Areas in compliance with safety regulations and guidelines from aviation authorities. These airports tend to have the necessary space around their concourses to maintain these safety zones, accommodating the operational needs while adhering to proper aviation standards.