Small plastic-frame drones have radar cross-sections below noise floor of legacy air defense radars

A DJI Mavic-class drone has a radar cross-section of 0.001-0.01 m2, which is 100-1000x smaller than a fighter jet and falls below the clutter rejection threshold of legacy air defense radars, meaning the firmware classifies the drone return as a bird or ground clutter and discards it. The operator never sees the target on screen. This persists because military radars were designed to filter out small, slow-moving objects to avoid false alarms from birds and weather -- the same filtering that enables reliable aircraft tracking actively prevents drone detection. Lowering clutter thresholds generates hundreds of false tracks per hour.