First U.S. Navy Jack (traditional): Historically probable first U.S. naval jack: Navy = fleet. United States stars: Stars + Navy = Starfleet: The primary authority of Starfleet, which is Starfleet Command, is located in San Francisco, USA. Starfleet vessels use the designation "USS", just like the U.S. Navy. "But they said it stands for United Space Ship or United Star Ship in Starfleet!" Yeah, they said.