What is NOT considered ground equipment in the provided list?

In the context of ground operations in aviation, ground equipment refers to various tools and machines that are utilized to support the functioning of an aircraft on the ground. Tugs, Ground Power Units (GPUs), and Air Start Units are all essential pieces of ground support equipment designed to assist with various operational tasks like towing aircraft, providing electrical power on the ground, and starting engines without needing the aircraft's engines running, respectively.

Safety garments, while crucial for protecting ground staff and ensuring their safety while working around aircraft, do not fall under the category of ground equipment in a functional sense. They assist personnel in maintaining safety standards but do not serve a direct operational role in aircraft ground handling. Therefore, identifying safety garments as not being ground equipment reflects an understanding of the distinction between operational machinery and safety attire.