Flags of the Imperial Union
At the request of President Herbert McWarren, Fleet Admiral Joshua Underwood designed for him a flag for the Federation. But he went further as well, designing his own flag (which he made the flag of Starfleet) and a battleflag for the SFMC Commanding Officer when he was on the field. He also made one for the Reydovan Empire. These all have the basic Confederate "Navy Jack" design used in the American Civil War, albeit with some degree of modifications.The United Federation of Planets

The official flag of the United Federation of Planets.

The battleflag of the Federation Starfleet, also the personal battleflag of Fleet Admiral Joshua Underwood, Chief of Military Operations.

The personal battleflag of General Jeremiah Neill, commander of the Starfleet Marine Corps. First seen in the Battle of Montagne Noire, February 1, 2391.
The Reydovan Empire

The flag of the Reydovan Empire, based on the outdated flag of the Chancellor. The twelve stars represent the twelve main systems of the Empire.