Flight Squadron Commanding Officer
From Star Trek : Freedom's Wiki
The Flight Squadron Commanding Officer (FSCO) is the Commanding Officer of all Combat Based Small Craft, such as the Void-Sphinx Space Superiority Fighter and the Mako Space Superiority Fighter. An FSCO is not usually seen unless there is more then one Squad of Fighters present. Further, the title 'FSCO' can be granted to multiple levels of fighting craft, from one squad to entire collections of fighting Wings, all dependant on situation.