The particles from a cometary debris cloud are typically very small, smaller than the diameter of a human hair, and tend to burn up at very high altitudes.
None reach the surface of the Earth.
Hence, there is no danger to the Earth's surface or to aircraft. In space, however, we have a different story. The result is that even a grain of sand the size of the head of a pin has the same energy as a .22 caliber bullet. At these speeds, the impact of a particle smaller than the diameter of a human hair can create an electrically charged cloud, a plasma, to form. This plasma can cause a sudden electrical pulse which can upset sensitive electronics.