Or another thought, why not have the warp fighters or alternatively unmanned combat fighters be powered remotely like those satellites were in that battle in the Chintoka system? They just have to stay at the carrier's perimeter and would have near unlimited endurance instead of having to come in every 24 hours to swap out a ZPE module...
Careful, the Enterprise could be unmanned too, since it has holodecks and can simulate people in them, one could then simulate the Enterprise and her whole crew, and then slave the holodeck controls to the actual starship, the holodeck crew could fire phasers and torpedoes. The problem comes with doing actual maintenance, but the holodeck characters could also remotely control actual robots from the holodeck to get that workd done as well. I think the Federation could have fully automated its ships a long time ago, but it deliberately chose not to.