A team of small drones, each resembling a small, sensor-laden helicopter, scoured a lush stretch of wilderness near Irvine, California seeking, among other things, surface-to-air missile launchers lurking in the brush. The missiles they found weren’t enemy ones. They were props for early test flights of the Ghost 4. The vehicle uses machine learning (the method behind most modern AI) to analyze imagery and identify targets, but it also relies on more conventional rules-based software for critical control and decisionmaking among swarm teammates.