At a Zodiac Aerospace (ZODC.PA) seat factory in the small town of Santa Maria north of Los Angeles, workers on the assembly line frequently sit idle, waiting for parts to arrive. The factory’s output has more than doubled in recent years, and much of the factory is working overtime shifts and weekends, workers say. The parts supply and other problems at the California factory offer explanations for Zodiac’s warning to shareholders on Thursday that it likely would fail to meet its target of generating operating income close to last year’s in the financial year ending on Aug. 31.