Which item is essential when towing at O'Hare Airport?

When towing at O'Hare Airport, having Towing Equipment Certification is crucial because it ensures that operators are knowledgeable about the specific equipment and the techniques required for safe towing. This certification verifies that the operator has undergone proper training, understands safety protocols, and is capable of handling various towing scenarios that may arise in a busy airport environment.

Towing involves significant responsibilities, including the ability to navigate safely around aircraft and other vehicles, which is why formal certification is not only beneficial but often a requirement for compliance with airport regulations. The other options, like passenger comfort stickers, self-driving capability, and celebration banners, do not enhance the safety or effectiveness of towing operations and are unrelated to the technical skills or expertise needed in this context.