From an engineering standpoint, liquid fuels have a far greater energy-to-weight ratio than batteries. Some of the largest advancements in combustion engines for the purpose of conveyance were made during the world wars. Noise was something they actively fought against. Loud tanks are scary, but unexpected tanks are much scarier. If they really needed it to be loud, sirens exist (see: Jericho siren). The energy-to-weight problem is only now finally being solved via modern batteries using exotic materials and processes well outside of early 1900's technology.